Allow HTTPS Redirect but turn off HTTPS login

Hi,

I have an RB750 with a hotspot server turned on. I do not want to buy an SSL certificate, so Self Signed certificates seems to be the best option.
However, when I turned HTTPS login on, it redirects to https:// login page, and the user will see the certificate warning.

Is there any way to change the $(link-redirect) variable so it does not use https:// URI, but allow HTTPS redirection to login page?

Thank you.

why not get a free certificate?
https://www.godaddy.com/ssl/ssl-open-source.aspx

Because actually I do not have a domain name with that name, because it is only for intranet only.