After reviewing this issue, we determined that having a Custom URL for the login was not feasible. Therefore it has been removed in version 1.7.1.
You can however, select a menu item that can be redirected to. The custom redirect URL feature was originally intended to be used to redirect to a custom form, but since we see that it might be used differently, and we are not handling any type of integration such as capturing the form username & password, it wouldn't work as expected anyways.
We are not sure why the redirect didn't work on your installation, all of our test proved successful.
I'd love to change the world... but they won't give me the source code!
