There is a patch out for support of forums by taxonomy menu.http://drupal.org/node/1473014
This will not work with taxonomy menu trails though.
First of all, patch was not accepted to the Taxonomy Menu yet, as I can see.
And Taxonomy Menu Trails calls Taxonomy Menu function that builds path the same way it does inside the Taxonomy Menu module. It works for the custom path building methods plugged-in to Taxonomy Menu. Have you tried it all together? Which versions of both modules have you tried?
I am working with the latest recommended versions of the 7.x-branch.
TM 7.x-1.4 and TMT 7.x-2.5
TM 7.x-1.4 does not seem to support custom paths.
Sorry for a delay.
OK, I'll write the test a bit later to check that.
Drupal is a registered trademark of Dries Buytaert.