As it ends up, for those who are now curious... Pear:
OAP support the HTTPs transport as long as CURL and OpenSSL are compiled into PHP. This is actually a most recent feature, and well PEAR
OAP is still only beta (0.83 or something like that).
So I finally did manage to get it working... the kicker is though, the API we are working with also require WS-Security based XML signing, which PHP can not presently do without a lot of ugly low-level SOAPing code... so in the end we are moving off of PHP and going to take the system to Perl *shrugs* which means I need to brush up quickly
