Application associated with itmss:// protocol

Hi there!

Were would I go to change the application that is associated with the itmss:// protocol (in Firefox)?

I have my iTunes library on an external drive and to make sure that iTunes doesn't start unless the external drive is mounted, I placed an alias to the iTunes application on my external drive and use that to start iTunes.

I would like to do the same for the itmss:// protocol. I get a confirmation message whenever I click on an itms:// link but there is no way to select a different 'application'...

In Windows (I'm new to the Mac), I'm sure I would found something in the registry, but I'm completely lost on the Mac! 🙂

So, anybody has some clues? Thanks!

Bruno G.
Montreal, QC