Multi card setup problem

Hi,

I'm having some trouble starting the Xservers. I own a mobo which has an
ATI mach64 chip onboard, and a Matrox G400 plugged in the AGP socket.
Whenever I start Xmga, the desktop appears on my mach64 and when I try
Xmach64 it says something like "can't find card". This is with last
weeks CVS. 
When I tried to track down the problem I looked for a good-old
Xfree86.0.log, but couldn't find it. Is there a way to turn on logging
or debugging of some kind?
This all happened on my LFS system with 2.4.22-xfs and 2.6.0-test9.
I'll be happy to provide more info, if someone could point me the right
docs, or the right commands.
Xmga does actually work on my mach84 with all translucents goodies and
dropshadows.

regards,

Koen Kooi

PS: please CC: me, because I'm not on the list (yet)