How do I configure what programs can be launched?

As an example of my problem: I have manually installed thunderbird under my home directory. It's registered as my default mail client, It's on my path, in my menu and has a launcher on my panel.

However gnome-do just can't "see" it like other applications that have been installed using rpm.

I've found some documentation on how to control where gnome-do looks for data files, is there something similar for applications?

(I'm using Fedora 8 BTW)

Thanks for any help.