XUL for Java: stucked (for the moment)

Remember This post: I just created a new java.net project to allow to use XUL declarative scripts out of the box with Java, and allow to bind them at will with Java code or even other scripting languages as well. The code comes from another project were it was working very well, but after extracting it from this project, I still have a big big problem with accessing some Javascript code from the XUL script (which makes the whole thing unusable of course for the moment). I know it's a trivial problem because the same use case works like a charm in the original implementation, I must have deleted the wrong line of code somewhere...