It appears that the ALSA drivers for some classes of sound chips (es1371, to be exact) are pretty buggy; the OSS drivers for these chips are a _lot_ better (like they actually work). It would be nice if system-config-soundcard would fall back to configuring the OSS driver if the user tries playing sound using the ALSA driver and there's no sound. It would significantly improve the user experience.
Hm, does the OSS interface work for you in FC4/5?
I'm still trying to figure out how to get that driver to load instead of the ALSA one, actually. That's the major reason for this bug. ;) Others who've had the same problems with ALSA and es1371 report that it does work, however.
I'm afraid you have to hack kernel if you want to use OSS, but if it's a user space issue I can add it to s-c-s.
I have no idea whether this is a user space issue or not; the kernel package maintainer would be the one to ask, I guess.
I'm afraid it isn't possibile to have two sound-systems in kernel.