Configure Ubuntu to boot directly into XBMC

Hi there,

I've set up ubuntu on a pc to use it as a HTPC. I'm dissatisfied with XBMCbuntu because all kinds of stuff doesn't work because they have stripped it down so much.

I'm wondering how to configure ubuntu to boot directly into XBMC, without showing the desktop. XBMCbuntu does it and Raspbmc too, so it seems possible.

Does somebody know how to do it?

Thanks,
Lukas