How to change the site URL from 'posted XX minutes ago via APPNAME' to something else as the Facebook login url used on my site

My company has a CMS... After logging in they can connect facebook to their CMS account.

If they post to their wall through our CMS something like this appears after their messages:

posted XX minutes ago via APPNAME

Now here it comes: (our case)

When they click on the APPNAME, they are redirected to the login page from our CMS system.

While we want to redirect the user to the promotional site of the CMS, which is on a different domain...

The Facebook app settings are telling me that the

App Domain(s) must be derived from the site URL

example:

we log in on www.xx.nl and our domain for the promotional site is yy.nl

Question:

can we change the redirect from the circled link without changing the 'site that uses facebook login' field in app settings? to redirect to a app page ? or even better directly to our promotional site ?!?!?!

im so confused, trying to get this to work for 2 whole workdays now...

thanks in advance guys!

Solution

I've solved it by changing the facebook redirect to something like www.xx.nl/?something=true. The .htaccess is now picking it up and redirecting to the promotional site.