Payment Order Lot

Hi

I would like to initiate a process of Refund With payment ECS.

So i have decided to initiate the Refund process by activating Payment order in the Payment method E.

Following Configuration activities done by me.

1.Maintain Document Types and Assign Number Ranges

2.Define Number Range for Document Type-PE

3.Define Default Values for Payment Order Lot

4.Define Bank Clearing A/c for Payment Lot

5.Release of SD for Refund.

6.Payment method E updated in SD document.

7.Run t-code-FPY1.

Now i have gone to t-code-FP45 to post payment order Lot.But inside the t-code-FP45 is asking Payment order no. from where i can get order no.

Kindly suggest me

Thanks & Regards

G Srikanth Reddy