Create an Opportunity Product record with Gift Entry?

I'd like to create an Opportunity Product (OpportunityLineItem) when using Gift Entry - I've managed to get the Opportunity.Pricebook2Id squared away, but I am struggling with the Product. 

Configuration:

• Created appropriate fields on NPSP Data Import Object (Product lookup, Quantity, Unit Price)
• Created an object group for Product (OpportunityLineItem) child to Opportunity in NPSP Settings/Advanced Mapping
• Mapped fields for Product 
  • ProductID -> PricebookEntryId
  • Quantity -> Quantity
  • Unit Price -> UnitPrice

When I try to run the Gift Entry I get an error message that user doesn't have edit to PricebookEntryId:

I'm aware that Product2Id is not editable, but  documentation states we should use PricebookEntryID for this case: The Product object is unavailable beginning with version 8.0. Use the PricebookEntryId field instead, specifying the ID of the PricebookEntry record

What am I missing?  Is this even feasible????

Thanks in advance!