[rt-users] customizing the ticket form

[GravyFace]

I'd like to be able to change the Update Type drop-down to default to
"Reply to Requestors" when the "Resolve" link is clicked instead of
"Comments (Not sent to requestors)".

What's the best way to achieve this?  If I need to modify/extend the
source, I don't mind doing so, just don't want to go about it the
wrong way and/or reinvent the wheel.

Thanks