Headers, Page Numbering Using "Different First Page"

I am working on a paper for an American Government Class. I am using MLA Format and trying to format the header. I have a Cover page and I am formatting the header with the box next to "Different First Page" checked. However, it will not allow me change the "Page Numbering" to start a 0 vs. 1. Is there a way there something I am missing? Is there no way to rectify this issue? The reason I ask is because if I use MS Word on my Mac it runs really slow and I keep getting the spinning wheel of death every few minutes. I would much rather us Pages if I can get it to do what I want.
Any information regarding this issue would be most helpful!
Thanks!