Where to sell a vB license?

[Ncturnal]

I bought a 4th copy of vBulletin (owned license) that I ended up not using. Where or how would you recommend I go about selling it. Since it was my forth, the price was a bit less than a customer buying their first copy. According to the vBulletin.com website, I am qualified to transfer the license if I wish since it is not presently in use and I've never transfered any licenses before. Any help would be appreciated.

EDIT: Actually, I just read the terms, and since the license isn't more than 3 months old, I can't transfer it yet, but it will hit the 3 month mark in January. Anyone ever have any luck getting a refund?