USB Back Track2

I'm currently copying the files across to my USB from the ISO but the main problem that I have encountered is getting the MBR to work. Apparently there is a script that will make the USB boo-table called bootinst.sh (for Linux and bootinst.bat for Windows) that comes in the boot folder of the CD. I have yet to try that. I have been trying various other method up until now but none of them have worked. I also while looking for a way to boot Back Track off the USB I came across a site detailing how to get your USB to multiboot using Grub. http://darksun.com.pt/mirage/usb_minipe_backtrack_knoppix.html. I also came across another tutorial on how to boot Ubuntu from a USB. At the time I didn't have much of a look at the site but it might give me another way to install Ubuntu without getting the invalid compressed format errors.
http://www.extremetech.com/article2/0,1697,2132615,00.asp