Non portable path separators

I have just passed from the old Visual Integration stuff, to the Visual Addin.
One "small thing" has changed that is a major problem for me... relative paths in #include files, now use non-portable separators.
For instance, the moc file will get:

#include "..\..\H\Dialog.h"

and not

#include "../../H/Dialog.h"

This means the generated files can't be compiled eg. on the Mac... not good for a portable tool kit
Because there is no XCode addin similar to the Visual addin, my XCode project use the files generated from the Visual project. Perfect method so far (1 million lines app), until... I use the Visual Addin...