How to create a gwt.xml file for an external jar?

I have an external JAR signpost-core-1.2.1.1.jar (from http://code.google.com/p/oauth-signpost/), that I want to include into my Java GWT project.

So I add this external JAR file to my build path in Eclipse and put theese imports to my Class:

import oauth.signpost.basic.DefaultOAuthConsumer;
import oauth.signpost.exception.OAuthCommunicationException;
import oauth.signpost.exception.OAuthExpectationFailedException;
import oauth.signpost.exception.OAuthMessageSignerException;

While compiling I got theese error messages:

[ERROR] Line 130: No source code is available for type oauth.signpost.basic.DefaultOAuthConsumer; did you forget to inherit a required module?
[ERROR] Line 133: No source code is available for type oauth.signpost.exception.OAuthMessageSignerException; did you forget to inherit a required module?
[ERROR] Line 135: No source code is available for type oauth.signpost.exception.OAuthExpectationFailedException; did you forget to inherit a required module?
[ERROR] Line 137: No source code is available for type o开发者_StackOverflow中文版auth.signpost.exception.OAuthCommunicationException; did you forget to inherit a required module?

So I put the following line in my Admin.gwt.xml file:

<inherits name='oauth.signpost.Signpost' />

And now I'm getting this message:

Loading inherited module 'oauth.signpost.Signpost'
   [ERROR] Unable to find 'oauth/signpost/Signpost.gwt.xml' on your classpath; could be a typo, or maybe you forgot to include a classpath entry for source?

Unfortunately the Signpost does not seam provide a gwt.xml file, since it consists only of a jar file.

So how can I write it?

And where do I have to place it?

Or do I just need to set some additional paths?

I don't know Signpost library but I suppose that you want to use it in your client side. Unfortunately oauth-signpost is only provided for traditional web services. Anyway if you want to use it, its possible only on server side where you have full support of jre 6. On client side you can use only provided gwt modules that use only emulated gwt-jre environment.