ORIGINAL: handyman 220
...............I have the TF P-40. I do not see a hatch, or a place it would be hidden.
Perhaps if you read a post or 2 which 'exposes' the hidden hatch, such as this one on the Top Flite P-47 ARF, you may get a better idea of what and where to look for:
http://www.rcuniverse.com/forum/fb.asp?m=8890682
IF is has the 'hatch', it will need to be cut out (balsa sheeting, stringers, and covering). What you will be looking for is double formers and stringers. The magnets are attaching magnets and dowels are already installed, but again: not obviously visible.