VPC – external hard drives?

Hi,

I want to install VPC on an external HD. We are attaching 500gig external HD’s to WinXP boxes, but want the virtual machine to sit on the external HD. I have attempted the installation, but get the “Virtual PC cannot find MSXML 4. Please reinstall VPC or install msxml 4. I registered msxml but obviously, that is doesn’t work. Can anyone point me to installation instructions of ext HD’s or if it can be done.

thanks,
diane