If you have a vanilla XP SP2 .HDD file with no other data can't you just go into parallels and change the HD size allocation from the default 8 Gigs to 15 Gigs... or is it better to have the disk space akllocation set to automatic so it uses what it needs? I take it Compressor would be a go thing to have running if HD allocation is set to Automatic...?
In a word no. To expand a virtual disk, read the sticky thread on how I expanded my disk and use one of the methods you find there. It's a two step process. Be sure to make a backup before you start.