Mozilla-firebird 0.7 + evolution in gnome

[Shi-ming Chen <shiming.cv90g@xxxxxxxxxxx>]

My preferred browser is Mozilla-firebird 0.7, and I want to try evolution.
When I click a URL in evolution, it  will  use  Mozilla-firebird to open 
it  after  I modify the prefernces-->Preferred Applications.

But, Mozilla-firebird don't know who to open "mailto" even if I modify 
the prefernces-->Preferred Applications. It says "mailto is not a 
registered protocol".

Does anyone know how to "register" the mailto protocol to Mozilla-firebird?
(This situation also happened in Mozilla 1.5. Dose Mozilla only accept 
its own MUA?)

Thanks a lot.