serial number

Hi all,

I am trying to do mb31 for a serialised component.

The equipment catagory is assigned as S.

External number range is assigned to this equipment catagory.

But at the time of saving when i am entering the serial number manually system is showing me a num range doesnot exist for the eqipment.

If i am assigning the equipment catagory S to internal number range the it is picking up the range.

Kindly help.