How can I manage to use 2 persistense units and make my app to recognize which to use?

I hava a JavaEE/ EJB3 application in which I'll need to connect diferent databases. It's on JBOSS 5.10GA. After I tried to deploy it I got the following error:

09:04:57,921 ERROR [AbstractKernelController] Error installing to Real: name=vfszip:/opt/jboss-5.1.0.GA/server/idiomas/deploy/idiomas.ear/ state=PreReal mode=Manual requiredState=Real
org.jboss.deployers.spi.DeploymentException: URL file:/opt/jboss-5.1.0.GA/server/idiomas/tmp/3j011-27cidj-gempz3rv-1-gempzqf8-9q/idiomas-web.war/ deployment failed
 at org.jboss.deployers.spi.DeploymentException.rethrowAsDeploymentException(DeploymentException.java:49)
 at org.jboss.web.tomcat.service.deployers.TomcatDeployment.performDeployInternal(TomcatDeployment.java:316)
 at org.jboss.web.tomcat.service.deployers.TomcatDeployment.performDeploy(TomcatDeployment.java:142)
 at org.jboss.web.deployers.AbstractWarDeployment.start(AbstractWarDeployment.java:461)
 at org.jboss.web.deployers.WebModule.startModule(WebModule.java:118)
 at org.jboss.web.deployers.WebModule.start(WebModule.java:97)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:597)
 at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:157)
 at org.jboss.mx.server.Invocation.dispatch(Invocation.java:96)
 at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
 at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
 at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:668)
 at org.jboss.system.microcontainer.ServiceProxy.invoke(ServiceProxy.java:206)
 at $Proxy38.start(Unknown Source)
 at org.jboss.system.microcontainer.StartStopLifecycleAction.installAction(StartStopLifecycleAction.java:42)
 at org.jboss.system.microcontainer.StartStopLifecycleAction.installAction(StartStopLifecycleAction.java:37)
 at org.jboss.dependency.plugins.action.SimpleControllerContextAction.simpleInstallAction(SimpleControllerContextAction.java:62)
 at org.jboss.dependency.plugins.action.AccessControllerContextAction.install(AccessControllerContextAction.java:71)
 at org.jboss.dependency.plugins.AbstractControllerContextActions.install(AbstractControllerContextActions.java:51)
 at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348)
 at org.jboss.system.microcontainer.ServiceControllerContext.install(ServiceControllerContext.java:286)
 at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1631)
 at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:934)
 at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1082)
 at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984)
 at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822)
 at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553)
 at org.jboss.system.ServiceController.doChange(ServiceController.java:688)
 at org.jboss.system.ServiceController.start(ServiceController.java:460)
 at org.jboss.system.deployers.ServiceDeployer.start(ServiceDeployer.java:163)
 at org.jboss.system.deployers.ServiceDeployer.deploy(ServiceDeployer.java:99)
 at org.jboss.system.deployers.ServiceDeployer.deploy(ServiceDeployer.java:46)
 at org.jboss.deployers.spi.deployer.helpers.AbstractSimpleRealDeployer.internalDeploy(AbstractSimpleRealDeployer.java:62)
 at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployer.deploy(AbstractRealDeployer.java:50)
 at org.jboss.deployers.plugins.deployers.DeployerWrapper.deploy(DeployerWrapper.java:171)
 at org.jboss.deployers.plugins.deployers.DeployersImpl.doDeploy(DeployersImpl.java:1439)
 at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1157)
 at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1178)
 at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1210)
 at org.jboss.deployers.plugins.deployers.DeployersImpl.install(DeployersImpl.java:1098)
 at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348)
 at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1631)
 at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.ja开发者_如何学编程va:934)
 at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1082)
 at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984)
 at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822)
 at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553)
 at org.jboss.deployers.plugins.deployers.DeployersImpl.process(DeployersImpl.java:781)
 at org.jboss.deployers.plugins.main.MainDeployerImpl.process(MainDeployerImpl.java:702)
 at org.jboss.system.server.profileservice.repository.MainDeployerAdapter.process(MainDeployerAdapter.java:117)
 at org.jboss.system.server.profileservice.repository.ProfileDeployAction.install(ProfileDeployAction.java:70)
 at org.jboss.system.server.profileservice.repository.AbstractProfileAction.install(AbstractProfileAction.java:53)
 at org.jboss.system.server.profileservice.repository.AbstractProfileService.install(AbstractProfileService.java:361)
 at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348)
 at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1631)
 at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:934)
 at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1082)
 at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984)
 at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822)
 at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553)
 at org.jboss.system.server.profileservice.repository.AbstractProfileService.activateProfile(AbstractProfileService.java:306)
 at org.jboss.system.server.profileservice.ProfileServiceBootstrap.start(ProfileServiceBootstrap.java:271)
 at org.jboss.bootstrap.AbstractServerImpl.start(AbstractServerImpl.java:461)
 at org.jboss.Main.boot(Main.java:221)
 at org.jboss.Main$1.run(Main.java:556)
 at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.RuntimeException: java.lang.IllegalStateException: Resolution should not happen via injection container
 at org.jboss.web.tomcat.service.deployers.TomcatDeployment$EncListener.lifecycleEvent(TomcatDeployment.java:483)
 at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
 at org.apache.catalina.core.StandardContext.start(StandardContext.java:4388)
 at org.jboss.web.tomcat.service.deployers.TomcatDeployment.performDeployInternal(TomcatDeployment.java:310)
 ... 67 more
Caused by: java.lang.IllegalStateException: Resolution should not happen via injection container
 at org.jboss.web.tomcat.service.TomcatInjectionContainer.getEjbJndiName(TomcatInjectionContainer.java:640)
 at org.jboss.injection.EjbEncInjector.inject(EjbEncInjector.java:80)
 at org.jboss.web.tomcat.service.TomcatInjectionContainer.populateEnc(TomcatInjectionContainer.java:482)
 at org.jboss.web.tomcat.service.deployers.TomcatDeployment$EncListener.lifecycleEvent(TomcatDeployment.java:471)
 ... 70 more
09:04:57,959 ERROR [ProfileServiceBootstrap] Failed to load profile: Summary of incomplete deployments (SEE PREVIOUS ERRORS FOR DETAILS):

DEPLOYMENTS IN ERROR:
  Deployment "vfszip:/opt/jboss-5.1.0.GA/server/idiomas/deploy/idiomas.ear/" is in error due to the following reason(s): java.lang.IllegalStateException: Resolution should not happen via injection container

If someone know what's going on... Cya!

Hard (for me) to tell whats going on, but it should work like that: create (define) one EntityManager for each database:

@Stateless
public class ManageSomethingBean implements ManageSomething {
  @PersistenceContext(unitName="firstDB")
  private EntityManager firstEM;
  @PersistenceContext(unitName="secondDB")
  private EntityManager secondEM;

  // some annotations
  public void storeSomething(Object value) {        
    firstEM.persist(new First(value));
    secondEM.persist(new Second(value));
  }

}

Now this bean should be able to use both databases (persistence units)