FM or BAPI to add line item to SD Delivery

I have created a custom function module to create SD deliveries with reference to a sales order from an idoc. In the case of a batch split the requirement is to add a new line item to the delivery instead of using batch split functionality. Based on searching other threads out here I am doing the following:

1) Create delivery with reference via FM RV_DELIVERY_CREATE

2) Change or delete existing line items via BAPI_OUTB_DELIVERY_CHANGE

Is there a FM or BAPI to add a line item to an existing delivery? I am trying to avoid a BDC session. We are on ECC 5.0.