Make Supplier Payment when list of bills includes refund

One of my suppliers sends an End of Month Statement which includes the occasional refund transaction. I enter each invoice received throughout the month by creating a Bill, then check the amount on the End of Month Statement so that it equals the total amount for all bills of that month, then pay the supplier. When I 'Create Supplier Payment' in MYOB however, it does not include the negative (refund) bills and the total to 'make payment' does not equal the total I actually paid. Therefore I am also not able to send a remittence.

I have to wait until the payment appears in my bank feed to then allocate the payment to the corresponding bills, however I would like to send the supplier a remittence.

Thanks in advance for any advice.