How do I edit the prefix protocols in a web browser?

Question

I use K-Meleon as my default browser, and sometimes it opens protocols in an external program or none at all. For example, if the protocol is aim: it would open in an AIM program. If the protocol is MMS, it would open up in Windows Media Player. My question is how do you edit these protocols to open in a different program?
Example. My favorite AIM program is TerraIM. How do I edit the aim: protocol to open in TerraIM?

Answer 1

change mms to rstp.