Thunderbird search not working for me

Hi,

I understand that since SOC2007 Beagle can search emails in Thunderbird.

I'm running Beagle 0.3.8 and Thunderbird 2.0.0.17.
Through the web interface, when I search a keyword which is in an
email, the results only show for example

>       Sent.msf 12 KB  october 18, 2008
> Filename	Sent.msf
> File type	source
> Result type	File
> Mimetype	text/x-csrc
> beagle:NetworkNode	
> beagle:OrigSource	Files
> Backend	NetworkServices

i.e. the whole tb files instead of the single messages.

I've created in my home directory a .mozilla-thunderbird link which
points to the real path of my tb folder, and added
/mypath/thunderbird in beagle-settings, but didn't help.

Is there something I'm missing to activate the thunderbird backend
in 0.3.8?
Do I need to install the beagle2.xpi file mentioned in
http://postlund.org/2007/08/06/thunderbird-support-now-available-in-trunk/
?

Thanks a lot, Marco