Export gerbers for the layouts, you can use the sparkfun cam file. Use a program like Viewmate ([From Pentalogix) and open up both designs. Viewmate has a layer move tool that you can use. Once your done you can print directly from Viewmate.](http://www.pentalogix.com/)
I have fought with this in the past with no luck. The only way I was able to do it is by playing around with gerbers, if you want to print directly from eagle then I have no solution.