I had the same problem and did this:
I installed Open Manager (could be done with other managers)
Copied the file like you normally would (on open manager)
Once done, quit the game, and open MultiMan back up manager
Once in MultiMan press load game on the one you copied AND make sure you have a blu ray disc in your drive (any)
Press no and it will go back to the XMB
The disc you have put in for example: Black Ops, should now say the game that you have loaded up.
So if you loaded Battlefield Bad Company, the black ops disc will say Battlefield Bad company etc.
Load the game and if have done everything right it will work!
To change the disc back to black ops just turn your ps3 on and off!
+Rep if i helped