That's a digital dream....but you should try with starting from zero find good script, modify it then market the forum.
Most forums have a quick reply function, and if it's not generally available, then you can usually get some plugins for your forum script. Without more information on your website (such as whether it is customly created, or if it's a ready made script), then it is harder to steer you into the best direction
after a quick google, I found the following information Admin CP -> vBulletin Options -> Message Posting and Editing Options -> Quick Reply -> Yes