Hie Bryan,
Sure, there might be some issue with new version. However, my point was to make sure that you have not created the certificate using OpenSSL. As with the said version of Integration Framework, SAP provides a certificate tool to generate the self signed certificate. You may grab some more information regarding the same with detailed documentation available in the integration framework version 1.22.0 or higher, (choose Start -> All programs -> Integration solution for SAP Business One -> Integration Framework -> Help -> Documents -> Operations Part 2.)
Regards,
Kuldeep