Hi Kıvanç,
Thanks for finding time in answering my question.
Initially we had added the field only to the structure KOMB. This enabled the field PO Type to be added to the field catalog and we had successfully created the condition table (Sales Org/ Distribution Channel / Division / Sales Order Type / Purchase Order Type), but then later we learnt that while adding the new condition table to the access sequence, the field (PO type) couldn't be assigned as it was not available in the structure KOMKBV1 or KOMPBV1. Hence we had to add the field to the structure KOMKBV1 and after that it could be successfully assigned to the access sequence.
Thanks,
Himanshu