You can do this by resource hacking.
Search the forums here and at Mess.be
There are a bunch of examples on how to remove things from MSN and which programs to use. You can remove users PSM by removing a part of the code in the resources for msgres.dll as far as I remember.
If you can't find it send me a PM and I'll find it and tell you. But try first so you can actually learn before you ask me to do it
Have fun!