Populate F03B13Z1 table for partially applied receipts

Hi all, 

I need to know how to populate the F03B13Z1 table when an automatic receipt has partially applied to an invoice. 

For example:

• Total receipt amount USD 1,000
• Invoice amount USD 800
• Amount pending (RU) USD 200

How should I populate this table? The desired result is to have the customer's invoice paid on F03B11 and a document RU for the pending amount.

If I complete the field RUCKAM with the total amount of the receipt (USD 1,000) and the field RUAG with the total amount of the invoice (USD 800), when executing the R03B551 program, it generates an unapplied receipt on F03B13/F03B14 tables for USD 1,000.