Approval route for negative amount (credit)

We are in JDE E1 9.0

We are usign P43008 to set up the approval route.

We use approval route P43008 with a thrid party Scanman to scan an invoice an then use the approval route to handle the voucher approval.

We would like to be able to setup approval route for credit but it seems that if I type a negative amount in P43008 the amount is converted to positive.

Is there a way to set it up uin JDE E1 to use the approval route for positive amount AND for negative amount ?

Thank you

mj