You only want to change the RAM voltage, which should be set at a default 1.8V (which is the required JEDEC standard). Then you would need to change this to 2.0V (on my computer, I would achieve this by selecting the +0.2V button).
However, G.SKILL seem to be pretty set that it won't work, so if you have an RMA number and are desperate to get 1066MHz RAM, then go ahead and get it swapped over.
Troy