So it doesn't work right now... damn...
If it worked well (hopefully), it would be a wonderful addition to the SmarterMail ecosystem...
I'd recommend SmarterTools contact Thunderbird development to see if they can work together...
Gabriele Maoret - Head of SysAdmins and CISO at SERSIS
Currently manages 6 SmarterMail installations (1 in the cloud for SERSIS which provides services to a few hundred third-party email domains + 5 on-premise for customers who prefer to have their mail server in-house)