Comment 1 for bug 429759

Sorry for duplicate comment, but maybe this program solves the problem better:

http://www.ubuntugeek.com/access-gmail-hotmail-yahoo-and-zoho-webmail-from-your-ubuntu-desktop.html

«Webmail for Linux Desktops provides a generic mailto: handler and webmail config dialog that lets the user choose his preferred webmail provider on first run and through the desktops Preferences->Webmail facility.
When clicking on mailto: links on your desktop or in your browser desktop-webmail will take care that the user gets redirected to his webmail of choice’s compose webpage with the proper fields pre-filled in.

Currently default webmail providers are: Gmail, Hotmail, Yahoo and Zoho.

Currently this is available for ubuntu lucid»

I guess you can get some code from that program or just offer users to install it.