WISPr-Redirection-URL

OK, so I’ve installed at least 20 RB450G’s and I’m fully happy with the device and it’s features. Er..OK, I have some wants, but that can wait.

Here is my current problem and questions.

I host my own apache and freeradius servers and use a custom remote login page.
Everything has been working great except I want to force users to a particular landing page using WISPr-Redirection-URL.

I send it via radius, MT gets it (as witnessed by the the RB450G log) yet no User redirect.
User ends up at link-orig every time.
I tried transparent proxy as one post suggested, nothing. (v3.28 and v4.2)

Is there a definitive guide on radius attributes? For example, does WISPr-xxx take priority or does Mikrotik-xxx?
If I have dst=“some page” set in the login form, which takes priority, WISPr or dst?

I searched this forum and came up empty.