Preemptive Price Adjustments?

[Luke <..hidden..>]

I'm wondering if there is a way in 1.2, to enter price changes 
preemptively.

I.E. I know that the price of part X is going to increase, because the 
cost is going to increase, on March first.  So I could (for example--this 
does not actually work) edit the part, set the updated date to 03/01/2011, 
and enter the new sellprice and cost.

Now, since my example does not in fact work (the price is updated 
immediately), is there any way to make this happen?

Luke