Thanks for the hint, it's fixed. I thought I tested the link!
Considering this module and future development of PW. Yeah, I was playing around with that yesterday, but couldn't see a solution. Unfortunately I knew this would one day lead to complications. :/
After little experimenting I think we need to rethink $page->url rewrites Multisite does in the admin and consequently in the front-end. I always feared it was maybe dangerous/adventurous and would lead to problems sooner or later. There's so many things to consider it's crazy.
So, after long thinking and testing, I'm heading towards letting the $page->url alone, to not get in the way as much as possible.
Then we just have to make sure 2 things:
1. when an url is viewed containing a "domain" in its path that is recognized, to redirect the correct domain/url. So a view link will just work.
2. to have correct url on the front-end output, we can parse the $page->render() output and replace/fix those urls output from templates and RTE's.
This way such new features like the "View" options work out of the box. Also cross Domain linking in RTE would work also.
I got a test version working so far but not sure about what to further consider with this new approach.