Today I downloaded the evolution-groupwise from gnome cvs and read some of the codes. Yes, those Ximian guys are quick hands. Referring to the code, I modified our hydrogen TRUNK to use AC_DEFINE in configure.in instead of -D of INCLUDES in Makefile.am. Ximian developers are busying working on the Evolution 2.0 refactor which can be seen from the Evolution Blog. Our hydrogen will change accordingly. That might be quite a work.
The JINI architecture is still too complex, I think. You have to run a few servers so that a simple example can work:(