Not sure where the limitation lies if the CPU has intel virtualization so, BIOS or some other chipset? Anyway seems like the hardware virtualization is a no-go, perhaps para-virtualization works at least.
You could try VMWare in Linux, I don't know which of VMWare's product you're using but I'm guessing VMWare Workstation - and that can be installed in Ubuntu too.
Perhaps a you already now but 2008 looks like it's not supported on the ML350 G4p: http://h18004.www1.hp.com/products/servers/windows/index.html