PeopleSoft Prepaid functionality

Hi All,

Here is the scenario, can you please tell me how PeopleSoft will work. This is common for all.

Step 1: I have a prepaid voucher for $1000 and posted and paid

Step2 : Later I entered regular voucher $600 and apply pre-payment to it.

How the accounting enrtries will work here? If the remaining balance is $400 , I have to collect the money from vendor..how to show in AP to reduce the $400 amount.. how do I clear the balance ??

Thanks