Well, you could create a system which can update the positions of your objects so that they always stay in a relative position to the window size, and stretch (with/without preserving the aspect ratio, maintain size relative to screen width/height) them as necessary.
Here's a thread where i posted how the end result should look like (proof that this is very much possible in C2), however it isn't made with the best practices and therefore would introduce bugs into something faster paced such as games: http://www.scirra.com/forum/your-c2-tests_topic41840_page57.html
Also, a direct link for the lazy: https://dl.dropboxusercontent.com/u/80437109/LimbaziLive/web-test/index.html
Something that i should mention is that you'll probably have problems with the touch controls / mouse input coordinates when using the scale outer mode, i had to re-create a new system (2 global variables for both the X and Y coordinates) that takes the viewport sizes into account, just to be able to precisely read the input... :/