What type of T1? If it isn't PRI, and it isn't a point-to-point, try this:
Dial 9 (or however you access an outside line).
Dial *82
If you receive dial-tone, you can then setup the 9 dest code to do a pre-dial of *82.
This will provide a "real" dial-tone, but the "fake" one that the MICS provides.