I have a Microsoft Virutal PC hard drive (.vhd format) that's maxed out it's 16 gig hard drive space. What would be the best way to increase this diskspace?

Booting into the machine (windows xp professional) and using the disk management snap in, I can see that the virtual drive has approximately 40 more unused gigs of space. Trying to use diskpart, I find out that Windows XP can't extend the boot partition.

So I'm at an empass, any suggestions on how to increase the partion or to increase the actual virtual hard drive would be great.

Note: The virtual hard drive is running on Windows 7 using XP mode.