Support system "log in" link for non registered


Support system seems to be working fine. All tickets are visible for registered users only, and the "log in" or register link appears. And it leads to standard wp login. But I would like to change that regular link to a custom one, I have a registration page made for that need, and the link is:

Also there is a check box mess (I agree) just check the page

So the question is, how to change the link to