That being said, my experiences with bootcamp have been less than stella. With XP installed and a piece of CAD design software (and that was it) it crashed and corrupted the OSX installation at the same time.
I don't see why you wouldn't be able to install the protools ASIO drivers within your XP installation and do what you intend... but to be honest, have you considered giving samplitude the flick and just using something designed for mac? The approach you intend could work, but if it were me I'd find it rather infuriating.
HD runs on PC... why not just buy a pc and stay entirely in windows? Call me a Mac-evangelist, but the day XP crashed was the day I threw my XP cd's in the bin.
