Boot Camp Not Finding Windows Installer Disk

I'm trying to install Windows XP on my Mac, it's running Lion, using boot camp. I open up boot camp assistant, and I've already downloaded the windows support stuff and burned it to a disk. Then, when i get to the next screen it asks me what size i want to make my partition, i set it to 60gb, i have my windows XP disk already inserted into the optical drive, then i hit install. But then a window pops up saying, "The installer disk could not be found. Insert your Windows installer disc and wait a few seconds for the disc to be recognized." My windows Xp is the full version loaded with SP2 already. Is there anyway around this? Or can i only install Windows 7?

PLEASE HELP!