iTunes Music Videos on PSP?

Does anyone know how to put the videos you downloaded from the iTMS on the PSP. When you download it, it shows that it's of M-Peg4 format, (like PSP) but when you transfer it to the PSP Video Folder, it says "copying XXX.m4a" (where XXX is the video name) to the MP_Root Subfolder. It should say "copying XXX.mp4", not XXX.m4a. M4A is a M-PEG4 format, but it's still not .mp4. I really need help. It works on my Video iPod but I also want it to work on the PSP. Anyone help me, PLEASE!