HTTPS connection issue on 10.8 (using self-signed certs)

I'm trying to connect to a server using a self-signed certificate. Everything's fine with OSX 10.6 - it pops up the "Are you sure you want to go here?" message, giving you the option to accept the risk - i.e. say "Always Trust", thereby adding the certificate to the Keychain, and then continue). But when I try doing it from my 10.8 machine, I get that "Safari can't establish a secure connection..." message. I did find another thread on this topic (http://forums.macrumors.com/showthre...8#post17780018), where the solution was related to lowering the network MTU.

That solution seemed to have worked for a lot of people, but hasn't as yet for me. I have a strong feeling that the problem is related to 10.8 and its Security Keychains, where it simply will not accept a self-signed certificate - it does not give the user the option to accept the risk and continue to the site. Has anyone else run into this problem?