your reply did not address my question. I already know how to deal with a partial receipt of PARTS. My problem is when the payment being made is not associated with a specific part or group of parts, but rather a percentage of the entire bill. 

Let's make the question simple. How do I account for a downpayment of 10% of the total order that is required by the vendor? This is not associated with any specific part or group of parts, but rather with the purchase order as a whole.