Force ATP on R3

With the move of the sales orders ATP into APO, one also has to move all other ATPs for that material. It's logical, but the change can be a pain. Sometimes developments exist in deliveries during the batch determination and it would be so much easier for the ATP to stay in R3 for the delivery check.

The function AVAILABILITY_CHECK has a very interesting parameter P_ATPCA-FORCE_R3 that gives credit to the name. If it is flagged it forces the ATP to be performed in R3. It can be changed from EXIT_SAPLATPC_001 with that common trick.

Dear lazy web, is there a better way to do it?