I need to change the 'Admin URL:' link on Pro Sites success page.

I need to change the 'Finalizing your site' page 'Admin URL:' link on Pro Sites.
when a customer signs up for a new site and completes payment the Finalizing your site message is displayed. under that message there is the users information and a link to their new site.
The issue is I need to change how that link is structured. It currently displays https://usersite.mysite.com/wp-admin
there are two things I need to change here.
1) I need it to go to HTTP:// because linking to HTTPS causes the site to display an unsecured warning as my subsites don't have SSL.
2) I cannot have them going to /wp-admin as I don't allow access to that, so I just need to remove that.

so the link structure at the finalization page admin URL should display: http://usersite.mysite.com

How can I achieve this?

Thank you!
Mike