The only work around i can think of is getting hold of,and using a "cracked" copy until the bug you talk about gets fixed.
It's not perfect by any means, but you HAVE paid to use the software - so it's definitley justified.
I used a cracked copy of XP, when i first started using paralells, just so i could play around with the VM config until i found settings that worked for me, without crapping out my genuine XP's key.
chrisj303