'PHP include' over a css background image?

I have a web page and in that page I have a div class called “header”. It is styled using CSS. In that “header” class I have a background image. I also have another web page that is just a navigation using .gifs with rollovers. I want to keep these two pages separate.

My question is this: Is it possible to use a ‘php include’ to place that navigation inside the “header” div class and have it also appear over that background image?

It seems pretty simple, but I am having problems making this work.

Thanks in advance.