Currently both key wrapping and encryption using RSA OAEP only support SHA_1. I would like to see support for more modern hashing algorithms like CKM_SHA224, CKM_SHA256, CKM_SHA384, CKM_SHA512 as deffined in the PKCS11 specifications (2.1.7 PKCS #1 RSA OAEP mechanism parameters).
Some HSMs also have a default algorithm they fall back to if 0 is passed. This could also be implemented at the same time.