Function module to add ID type into BUT0ID table not working.

Hi all. We are trying to add data to the field "ID type" into the table BUT0ID. When we do it manually in the BP t-code, the data gets into the BUT0ID table. However, when the same is done through the use of Function Module(FM)- BUPA_IDENTIFICATION_ADD, the data does not get stored into the BUT0ID table. What could be the reason. Please provide a feasible solution.