Statistical SO line item not relevant for billing

Hi,

For a Replacement Order, when we tried to create a Proforma Invoice from a delivery document , I am getting the below error

"59659855 00010 Statistical SO line item 73478344 0003 not relevant for billing"

The Item category is Free of Charge Item

Billing Relevance Indicator is D (Relevant for Proforma)

In Delivery Document, The Intercompany Billing Status field is Relevant.

Can any one let me know how to create Proforma Invoice for that.