SNMP V3 SHA Auth and AES Encryption Support

We are using NET+OS and SNMP V3 and have an initial working application. As we understand it, the Treck Stack only supports HMAC-MD5 authentication and CDC-DES Encryption. If we wanted to add SHA authentication and AES encryption are there any hooks to get called and implement our own? I imagine that even if this is possible it is not trivial, so if anyone has done this are there any samples or white papers?