Creating Callbacks


I want to make the “Time Worked” field a mandatory one with each ticket
update. I believe this can be achieved through callbacks. The problem I
have is that my perl foo is very limited. I was thinking of using the
MandatorySubject plugin as a starting point for my own callback
(hacking at it till it works) but not wanting to re-invent the wheel I
was wondering if anyone already has something like this in their rt
instance, or if someone is willing to lend a hand with it.

Regards, Jim