Documents for Payments

Dear All,

I want to somewhat replicate the functionality of Incoming/Outgoing payment form.

I want to create a user defined form with a field for selectipon of BP. When the BP is selected, it should display in a matrix all the documents for payment. Just like it does in the standard SAPB1 incoming/outgoing payment form.

Is there any DI object which can return me all the open documents for payment for a BP?

Please help. Cany code samples will be great.

Thanks,

Satish.