Price Condition only for Invoices and Return Orders

Hello,

I have an issue regarding an invoice price condition.

The requirement is that a specific discount price condition to be applied only in the invoice document and after that copied in the return orther if ther is such an order.

I managed to exclud the price condition from the quotations and sale orders and to add it in the invoice document. But the problem is that the discount price condition from the invoice has no value.

Can someone please guide me through this?

The  discount price condition is define as shown bellow:

Condit. type:  ZR01

Access seq.   K307 Customer with Release

Cond. class:   A Discount or surcharge

Calculat.type:  A Percentage

Cond.category:  E Cash discount

Plus/minus:    X Negative

In the Pricing Procedure ZPN001 the discount condition ZR01 has the following routine:

Requirement (Routine) :  24 Only in billing doc.

In the copy control from the delivery to the billing there are  the following settings:

Copying requirements:   004  Deliv-related item

Data VBRK/VBRP:         900  Inv.Split (SO no)

Billing quantity:     B

Pos./neg. quantity:   +

Pricing type:         G

PricingExchRate type: C

Thank you!

Daniela