Booting to XP on USB (installed on internal HDD in same machine)

Hi,

I like to run XP on a Vista machine (Acer 5720).

There are many info on installing and running XP on a USB HDD....

But...

My question is:

If I put a new, blank HDD into my laptop as an internal disk and install an XP on it, can it boot later as an USB HDD after I have put back the original Vista ?

Of course, instead of the multiboot option I set the boot device in the BIOS....

So ... Would that work?

Does XP install itself "remembering" that it sits on an IDE HDD or just happy to find the MBR on the boot device ?

Thanks !

Attila