Posting Options to appear in the Postbit

[Lucky Seven]

I'm looking into a customisable RPG scheme on my forums which would be a forced style in the RPG forums, and what I want to do as part of that is have two extra fields when posting that will go into the postbit section of a post. I've looked around vbulletin.org for already created solutions but found nothing suitable (the closest - here - was a mod which added the posting fields but into the message part of a post). I believe it should come from PHP file edits as well as modifying the templates but I'm not sure exactly how to do this so any advice would be fantastic.

I think my main issues in this are a lack of understanding when it comes to the PHP files. What my thoughts on this are is there must be some way to duplicate the effects of the value/name status for the $title field in newthread/newreply from the PHP files and that should solve the issue. But then again, I don't have much experience with PHP files besides following step by step instructions such as those from the mods found here since I've never took the time to think about why certains things to what they do.

So, in short, it's about getting two new posting fields but limiting it to specified forums (which should be easy done with the forced style). I'm using vB 3.6.5.