I've updated my graphics card drivers (GeForce 5200Fx), now it should support OpenGL 2.0 -- and the tests are running without any further parameters, i.e. the feature is now enabled and everything is fine. So it was a problem with my drivers. Anyway that issue should be addressed by the framework.
I'm documenting my personal "getting started" and maybe I make a document out of it, but I can't say that for sure now.
Concerning the Eclipse project issues: I made xith3d and xith-tk plug-ins, and added a dependency from xith-tk to xith3d. I'm currently developing a graphical editor plug-in using Java3D, but due to problems in the AWT-SWT-bridge on Mac OS X I want to port all that AWT stuff to SWT. Maybe I'll change to Xith3D and port Xith3D to SWT, but I'm not sure if I've got the time for that. On the other hand I really want my editor to work on Mac OS X :-) But if I'm going to use Xith3D, I'll use it as an Eclipse plug-in.
Since may own framework is using floats, I guess Xith3D will fit better than Java3D (I've read that using floats instead of doubles is one of the differences between Xith3D and J3D). I have to run some tests before I decide to change to Xith3D. What would you say are the main differences between Xith3D and Java3D, comparing the latest versions of both frameworks? Since I'm not developing a game or animations, performance isn't a problem in my case. But I need transparency and I found the Java3D transparency to be handled very difficulty. Also the quality of 2D text is very important.