Hello, PM me your email address and ill send you a copy of the SID 5.10 manual .... Its wort having a browse through chapters 4 to 9.
(it mentions XBMC on the installer but thats a special USB version, forget that for the moment)
Its a simple process, roughly :
Copy the files from your memory card to the xbox hard drive
insert MechAssault, select `campaign` then select `Run Linux`
you will be greeted with the Softmod menu
Click on `Backup / Restore features`
select `Create MS Backup`
Then once its done its stuff
Click on `Install single boot Softmod`
Then click `Standard`
Then `UnleashX dashboard`
And thats about it ....... To get XBMC on your xbox i recommend using XBMC Installer Deluxe :
Auto Installer Deluxe - Softmod Installer Deluxe - PSP Installer Deluxe | Official Torrent Tracker
Boot up with the XBMCID disc, use the `Softmod` section and install XBMC as your main dash to the E partition.
Reboot and your all done
There are other ways to achieve the same result, but this is by far the safest method, AID - XBMCID & SID are made by the same guy so they`re all compatible with each other.