had a similar problem myself. When you say the GRUB and/or LILO installation failed do you mean it wouldn't boot after installation? This is the problem I had and it was due to the RAID support being loaded as a module and not compiled into the kernel. The easiest way round this is to create a new initrd that pre loads the RAID support.(Easier then compiling a new kernel!!) Then just configure LILO or GRUB to load that intrd and all should be well.