Harald;

I'm also new to chuck and this list.
I'm a hobbyist musician and software engineer.

Welcome on board!

And on the other hand I couldn't create more than one (working) LiSa
objects at the time (is this right?).

Fortunately that's not correct. You can use quite a few, if you like;
LiSa a => dac;
LiSa b => dac;
//etc

If this gave you trouble there is likely something else that went wrong. If you send a (minimal) example that demonstrates the trouble you had we can look at it and try to help.
 
So it seems I cannot record and save stereo sounds to files?


Not right now, no. This is clearly a missing feature.
 
So as being a software developer myself, I tried to look into chuck's
source code and explored if I could solve some of these things.


Cool!
 
(Note that I am experienced in other fields but totally new to sound
programming)


As long as you stay away from spectral analysis and filters I think you'll find that the math is quite easy, most of the time. Various online and printed tutorials on DSP exist may also help.
 
I then also managed to change SndBuf (in a quick and dirty way) to be
used for recording. But I didn't manage to save this as a stereo sound
file.

Did you do that because WvOut, didn't suit your needs, or did you perhaps overlook it? Maybe this was a result of your problem with LiSa? I don't think this should be needed, but perhaps your needs are somehow unique.
 
My main problem was that I don't really understand how multichannel
and buffers are supposed to work.

Dan announced once that he is working on a multi-channel version of LiSa. This might suit your needs?
 
I see it is in the design at many places, but it seems to be unfinished.

I agree.

It is also very unclear to me, how chuck development is coordinated.
An integrated system like sourceforge would make this more easy, as
all the development is (virtually) bundled in one place. How should
external developers contribute to chuck?


I think there was talk of a CVS repository. I'd be interested in this too; I've been writing some new "nodes" (the local term for UGens) for Fluxa (the livecoding synth that goes with Fluxus) and I would be happy to try port some of that to ChucK too.

Aside from these topics; I too am quite excited about the news of a upcomming new release. Full steam ahead!

Yours,
Kas.