Xorg: getting VESA working

[Mumia W.]

I have via onboard graphics, and I can get into X using the via driver, 
but I can't trust it too much since it sometimes crashes my system hard, 
so I want to get VESA working.

Getting Xorg to use "vesa" used to be a breeze in Debian Etch, but it's 
not working in Ubuntu Hardy. I created a config file for vesa, but it 
doesn't seem that vesa is even probing for the video modes. Here are my 
Xorg.0.log and xorg.conf files:

http://home.earthlink.net/~mumia.w.18.spam/docs/Xorg.0.log
http://home.earthlink.net/~mumia.w.18.spam/docs/xorg4.conf

I read this document:
http://www.x.org/wiki/FAQErrorMessages#head-83b2f9b8c18db15e641ed9e0be8f9a8364001e5b

But it doesn't really seem to explain why vesa fails, because VESA never 
outputs the 'Not using default mode "xxxx"' lines. Is vesa even trying 
to find modes?

I've been informed earlier that this may have something to do with 
missing RandR support in the vesa driver; if so, I have no problem 
manually including modelines in xorg.conf if that's what's needed (so 
long as I know what to put in there).

I'm using Ubuntu Hardy i386 with 512MB of RAM. Please help me get vesa 
working again if possible.

Thanks.