After changing players positions, they revert to how they were.
If I want to swap my two wingers just before the game this is what happens :
1. Load up the tactics screen
2. Select LM
3. Swap with RM
4. Upon looking at the positions now, they are in the correct place
5. I press Comfirm
6. I am taken to the squad page, I check the Tactics page once again
7. The changes have not been saved at all
This was present on 2011, and just letting you know it is present on 2012 also. This is the case with swapping any positions, not just wingers.