Hi Jon,
Yes...we do support T.38 and CCM 6.0
What is your current setup?
Sr140 -- H323 -- CCM -- MGCP ?
In 4.2(3) and 6.0 afaik when CCM downloads the config to the MGCP, it no longer includes the T.38 FAX inhibit command....which is a problem if you don't have a gateway IOS version that supports it:
12.4(7.12) / 12.4(7.14)T or later.
To be honest I have only tested in 4.2(3) but should be the same logic.