XenForo 2 redirect_to parameter on Login URL not working

I just upgraded to V2. In V1, I had login links with redirect_to that let users to redirect to that URL after login. But this is no more working after i upgraded to V2.
Adding this here in case others find it searching the same problem. I could not make xf_Redirect work either, but here's what I found in my testing:

- xf_Redirect appears to be ignored if the redirect is to a different domain. It may also fail if http:// is in the url, I'm not sure.

- xf_Redirect works perfectly when redirecting to a file in its root directory. I set it up that way and made a file in the XF root that redirects to the desired url

An ugly hack but it works.