You can also manually type the quote tags.
Example: [quote = username]quoted message[/quote]
Or I think that's it anyway. Too much of a lazy snob to verify but that's the setup on another vBulletin message board. Just leave out the spaces I have in between the = symbol and the two words in the first set of brackets.
!Edit!
Ran out of time to edit my previous post so this is a follow up with the necessary correction.