AST transformations don't work

If I use gmaven to compile groovy source code with AST transformation (eg. @Bindable), it is not applied in resulting class file.
I've selected 1.6 provider, which uses groovy 1.6-RC-1 by default.
Simple project is in attachment test1.zip

If I try groovyc (from 1.6.0) for the same thing, it works - the resulting class file is bigger and contains words like "PropertyChangeSupport"

So I've tried to force gmaven to use groovy 1.6.0, but I'm getting

[INFO] startup failed, /C:/tmp/groovytest/test/src/main/groovy/test/Example.groovy: Not an ASTTransformation: groovy.beans.BindableASTTransformation declared by groovy.beans.Bindable

and if I run mvn with -X I still see the org.codehaus.groovy:groovy-all:jar:1.6-RC-1 dependency there
attachment test2.zip