stock transfer requisition for non-valuated material

Dear SAP gurus,

We are using non-valuated materials extensively in our company; and we are having scenario where people in one plant would need to request material from other plant. We will use Stock Transfer Requisition for this.

However I found one strange thing. When we create Requisition for stock transfer (item category U) for a non-valuated material, I got error message asking me to put valuation price. This puzzle me because this is obviously a non-valuated materials where we dont even have accounting view for this material.

Please help.

John.