SB has a nice HELP page on how to get certificates and configure your SmartBear server to use secure HTTPS rather than HTTP. With both FF and Chrome now giving warnings when any password web page...
The problem is that the installer would need to generate self signed certificates on demand (to match your installed domain name). The end user experience would then be worse: instead of "Not secure" being displayed in the bar at the top, you will get big, scary, full screen security warning and then have to click the small grey link to say, yes, you do trust the site.