Congress - DMK 2011 TN Assembly Elections Seat Sharing Deadlock

With 18 MP's in the Lok Sabha when DMK was able to ask for and get 7 ministers at the Centre,what is withholding or preventing the DMK in accomodating Congress demands in the 2011 TN Assmblly Election Seat Sharing
This is the time for the DMk to reciprocate which the party is not doing
There is reason to believe that  the conflict is more than just about seat sharing