FIFO Valaution

Dear Experts,

Requiremnt is to configure FIFO valation,

1) is it possible to activate FIFO costing in SAP retroactively?

2) The configuration of FIFO Valuation involves MRLH but i have a error "Function currently not possible" What could be the reason.

3) When using OMW4 for FIFO valuation is it important to use the LIFO tick ?

Any guidence would be really appreciated

Thanks

Edited by: Shehan_D on Sep 26, 2009 1:05 PM