I don't think it'll work. The T45's only came behind 4.6 engines (in the Mustang) and they have a different bolt pattern than the SBF. The T45 doesn't have a removeable bellhousing, so you can't swap it out for a SBF bell.
Keisler makes a front plate for this swap. My concerns with it are two fold: 1: The T-45 does not have the best reputation out of the box. That being said they can be made tougher but I don't think the expense is worth it (my 0.02) and 2: The adapter from Keisler completely undoes the rigidity of the modern bell structure because it returns to the 4 bolt pattern and uses the standard bell. The T-45/T-56/TR-3650 transmissions were specifically designed to have a 'many' bolt bell/front cover (T-56) or integrated bell (T-45, TR3650) to distribute the torque in the light weight case.
Well, ok then. No T45 for me. I have been looking for a t5, I was hoping that this trans was similar. Guess i'll have to find something else, I would even settle for a toploader, I really don't like the auto.