Apply a Discount tier basis rule based on extended amount of SO, regardless the pricing UOM of items

Summary:

How to apply a Discount tier basis rule, based on extended amount of the sales order, regardless the pricing unit of measure of priced items ?

Content (required):

Hello, 

In our current project we implement Order Management with Pricing Management.

Our need is rather classical and we assign the strategies to Business Units and Customers.

In our price lists :

• Some items are priced in Kg.
• Some items are priced in Ea.

We want to implement a discount tier basis rule, based on extended amount of the sales order.

“If the total sales amount of the order is between X and Y, then apply discount.”