Scheduling Agreement -Schedule line should not pass the requirement to MRP

Question

Hi Friends!
As we all know the scheduling agreements is outline agreement with future schedule lines, with this system will  pass the requirements to MRP for the schedule line which is even after 5 years, so my requirement is  if the schedule line date is above 15 days from the current date then requirement should not pass to MRP. 
solution which we gave is, SA initially will determine the schedule line category as  CN (which will not transfer the requirement) and  a batch job program will run daily and it will check for each schedule line if any of the schedule is with in the 15 days from the current date then it will change the schedule line category from CN to CP. 
Now the problem is , by using Batch Job which program I have to call to change the schedule line category?????
1. we tried BAPI_SALESORDER_CHANGE but when we are changing the CN to CP it is not performing ATP where as if we do manually it is performing.
2. we tried BDC but here also we facing some strange problem i.e. while recording the ATP screen is not populating where it is coming while doing manual.
Can someone let me know which one program we should call in Batch job to do this change.
Regards
Nath

Answer 1

Hi nath,
i also failed in changing shedule line category in userexit and in BAPI.
in one case, i succeded in doing it with a bdc after MV45AFZZ / userexit_save just bevore the datas are reset but after the commit-work is processed.
the other possibility is, to change the accepted amount in userexit RV03VFZZ / USEREXIT_AVAILABILITY_OUT.
3. possibility is, to block the order with a delivery - block , same as the credit-control-block. This block can be set in MV45AFZZ or perhaps in BAPI too.
hans