Inventory valuation

Hi,

One of our customer evaluates its stocked items according to the ‘weighted average, date’ inventory principle. At the same time - due to some specific legal tax regulations - the customer needs to evaluate its stocked items according to the LIFO principle. He plans to do this by using different posting ledgers (current & tax). Does anybody have experience with adjustments to the standard of Dynamic AX in this area? Any hints / recommendations / comments would be highly appreciated.