Thanks for posting this. I had to disassemble mine to remove stuck batteries. None of the tool supply stores in my town sell small Torx drivers (I checked all seven) but after finding this thread I was able to order the right driver.
I have discovered the hard way that Eneloop XX batteries are too large to fit in the TBP12. I'll have to remember to use these in my Audio-Technica transmitters, and my Energizer batteries for my Line6.