Editing soundfonts. How do I do it?

[Sascha Franck]

Well, I doubt there's a comfortable way to edit SF2 in case you don't want to spend some money.
The only "realtime" SF2 editor (read: you can play the sets you're just editing) still seems to be Vienna - which after all isn't such a brilliant editor either.
So, whichever editor you may use, you will have to save, update in your playback module (sfz in this case), try things out, switch windows back to the editor, work further on the patch, switch back, update patch, try out, etc etc...

If you REALLY care about this issue, I can only recommend getting a sampler loading SF2 fine and then tweak them after they are converted.
VSampler seems to work nicely with SF2 and is cheap.
I wouldn't recommend it though because the interface is... hm, I'm missing appropriate words (I'm actually not missing them, but they wouldn't be politically correct...).
Better look into saving some money and getting Kontakt or HALion (or perhaps Mach5). Yes, a rather expensive solution, I know, but in the end I'm sure you'll be happy in case you're using sampled patches a lot.

I remember there was a freebie SF2 editor which was even supposed to be better than Vienna - but I actually forgot the name as I never really used the SB card I had back then.