Prepayment with AWT Applied to Standard Invoice

Hi,

Is it possible to offset the AWT of a prepayment applied to a standard invoice?

See example below.

Prepayment

     Amount          100

     AWT               2

Standard Invoice

     Amount          200

     AWT               4

After the prepayment is applied to the standard invoice, is it possible to automatically have a net of 100 and AWT of 2?

Thank you.