You can still make your own xorg.conf and put in the emulate3button option. If you plan on using the drivers from genesi you'll probably need to create one anyhow:
http://www.powerdeveloper.org/forums/vi ... php?t=2238
I can't remember what section it is under, so you'll need to create that section and put it in manually.
What xorg will do is autodetect whatever is not in the configuration file.
A quick googling around found this:
Code:
Section "InputDevice"
# generated from default
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/psaux"
Option "Emulate3Buttons" "yes"
Option "ZAxisMapping" "4 5"
EndSection
I haven't tried it myself, so don't know if it works, or more information is needed in xorg.conf.