Thanks for the feedback. I know that the old corner exploit still works, I posted a thread about it a while back on FM12. You can try this too:
http://www.fm-base.co.uk/forum/football-manager-2012-discussion/103143-how-add-corner-exploit.html
Tell me if you have problems creating it.
What exactly does this exploit achieve? is it forcing the opposition markers to be marking the lurking players, leaving the box open?