User Exit MD11 - Very Urgent

Hi

I have found two user exits for MD11 transaction.

LMDR2001 User exits restr. profiles of opt. pur.ord.-based load bldg

LMDZU001 User exits in additional planning

But control is not stopping in either of these exits when I execute the transaction MD11.

Can anyone pls help me where exactly these exits are used in MD11 transaction.

raghav