Manipulating the overlay's parent window

Hi,

How can I control the overlay's parent window url from my custom module code?
I'm inside a node form and I want to change the destination of the parent window without leaving the current overlay.

Basic scenario:
- node/%/edit is displayed in overlay
- user hit's submit
- form is rebuild, user stays in the overlay but I want to make sure that once he closes the overlay (without any further form submission) he will be seeing a specific page

I can't seem to find a way to do this. When I try to use the $form_state['redirect'] property with an array(url, array('fragment'=> '...')) then the fragment get's stripped, see this post:
http://stackoverflow.com/questions/7691460/using-fragment-in-drupal-7-form-redirect

Is there any way I can control the parent windows url from inside my module? By setting an undocumented javascript setting maybe?

thanks and best regards,
hadubard