Invoice Plan PO upload using LSMW(BAPI and IDOC)

Hi

I have a lsmw in which i have used BAPI to upload invoice plan purchase order for a cut over.

I am seeing that a particluar invoice type (quartely and half yearly) purchase order is not getting uploaded.

It throws a message that "Entry 56(code for half yearly invoice plan type) does not exists in FPLA.

I had checked the TFPLA table to see if the master data for code 56 exists and i am seeing that the entry is available.

I am able to upload PO's with invoice plan types monthly and yearly with out any issues.

would like to get some light on this if anybody had faced this kind of issue.

Thanks

Harikesan