Do any of the CA XCOM for z/OS support SHA-2 certificates?
Release: CA XCOM Data Transport for z/OS 12.0
SHA-2 certificates requires OpenSSL level 0.9.8o. The highest level of OpenSSL implemented with CA XCOM r11.5/11.6/12.0 is OpenSSL 0.9.8h, which is a lower level than required to support SHA-2 certificates.
In order to support SHA-2 certificates you would need CA XCOM r12 installed and IBM System SSL certificates implemented.