[Xmonad] initialization when running xmonad using xnest

I'm not ready to switch to using xmonad 100% of the time yet, so for the time being I'm running it using xnest. The problem I'm having is that I don't know how to get xmonad (or xnest) to read an initialization file (e.g. a .xinitrc file) in these circumstances. Does anyone have any suggestions? Thanks in advance, Mike