Adding a Groovy Class to a Google App Engine Project (groovy-plugin, google-plugin)

I've heard that GAE now supports Groovy, but it seems the plugin开发者_如何学JAVAs don't work so well together. I'm trying to make a GAE project in eclipse that I can add Groovy Classes too...but it won't work. Everytime I try to add a Groovy Class I get the error 'Project is not a Groovy Project'. And when I go to Configure - Convert to Groovy Project, and try to integrate a Groovy class...I get the following

java.lang.NoClassDefFoundError: groovy/lang/GroovyObject

Is there any way to get these two plugins to work together?

I love the easy testing and deployment from the GAE plugin, but want to benefit from things like the XMLSlurper of groovy.

Why do you need to add asm-3.2.jar ? This should be integrated in groovy-all-1.7.0.jar

I seem to have gotten it working, but i'm not sure it's the correct way. I've right clicked the project and select "Configure - Convert to Groovy Project" and added both the groovy-all-1.7.0.jar and the asm-3.2.jar to the war/web-inf/lib folder and referenced them both in the class path. The project will start. Can anyone confirm this is the correct way of solving this problem?