Just as a note in case anyone is coming here looking for a solution to this issue after a 11.04 -> 11.10 upgrade, you need to remove thunderbird and thunderbird-globalmenu and then re-install both, then go to 'setup mail'. This seems to trigger the integration into the messaging menu.
Just as a note in case anyone is coming here looking for a solution to this issue after a 11.04 -> 11.10 upgrade, you need to remove thunderbird and thunderbird- globalmenu and then re-install both, then go to 'setup mail'. This seems to trigger the integration into the messaging menu.