Sending mails by right clicking on a file: how to replace Evolution?

[Stegozor]

Wade Smart wrote:
> 08232006 1256 GMT-6
> 
> type about: config in firefox address bar.
> Scroll down to
> network.protocol-handler.app.mailto
> 
> the value needs to be Thunderbird.

Are you sure? I didn't have these values in Firefox and Thunderbird, so 
I added them manually, the value of the field is now a string: 
"Thunderbird" (without the quotation marks).

The problem is that nothing changed. I also relaunched the window 
manager, but that didn't help either. By right clicking on a file and 
then on send to... I still have Evolution as the sole suggestion, 
nothing about Thunderbird.