Cordova Communicating with Iframe on Different Protocol

Is there a way for an iframe using the http:// protocol to postMessage the parent window which is on the file:// protocol?

Here is my setup:

[main cordova app on file:// protocol]
    [iframe on http:// protocol]

So i need to postMessage from the iframe to the main (parent) window. Every time i try this i get a security error telling me that the domain and protocols need to be the same.

Is there a way around this using Cordova?

Thanks Dave