How to set email client for firefox?

[marc]

In Jaunty, when I click a mailto url, the wrong email client is used. 
System settings/Default applications is set to the correct email 
preference, but clearly this is being ignored.

It's also possible to set the email client in FF via Options/Prefs/Apps/
mailto. However, the only entries on there are evolution and Yahoo mail!

First, I think this is a bug, so will raise it, but any idea how do you 
change the "default" applications in FF Pref/Apps?

-- 
Best,
Marc