How to handle deposits (downpayments) and retention in Project Billing?

   Hi,

Does anyone knows how to handle Deposits and Retention in Project Billing? This means that for every billing interfaced in Receivables, invoice amount will be net of Discounts and Retention.

Example: Billing amount is 100,000

Downpayment is 10%

Retention is 10%

Billing amount = 80,000

Computed as : 100,000 - 10,000 (10% Deposit) -10,000 (Retention)

Appreciate any help

Thanks