You may be making this harder than you need to. Just because a server presents you with a certificate does not necessarily mean you have to do anything with it. You may need to explain more about the unusual server you seem to be dealing with.

When sucking data from http or https servers, I typically use the 'wget' command line tool. This tool handles standard auth login. While it is not a OS-Independent or Pure-Perl solution, but it sure gets the job done with ease.