MTM valuation of stock

Hi

I have the requirement to find out the solution (direction) for the physical goods in Material Management valuation according to Mark to Market principles (use price on the commodity exchange). In FSCM TRM securities and derivatives can be valuated according to MTM but how to do this for physical stock of commodities (aluminium or wheat)? The standard cost in MM03 (display material)  is not linked to TRM.