You might be better off not using the vox setting on your radio if you've got an Autocom box as well. My Autocom (Pro-M1) has vox support (no surprise there) but it means my radios don't need vox support themselves. When the Autocom is set to Vox operation, getting the Autocom vox to trigger 'virtually' presses the PTT switch on the radio. Requiring the radio to then trigger itself using it's own vox support might make the response a bit too slow for CBTs.
FWIW, I use the PTT switch on my handlebar for most training rides and never use Vox. For CBTs and demo rides with commentary I set the Autocom to transmit permanently so I can just concentrate on the chat.
Cheers, Norm