Hello Niu,
The SAP NW version that you are using is too old and doesn't support SAML 2.0.
We usually recommend to customers to consider an upgrade if they want to benefit from the new technologies/capabilities we offer.
If you anyway decide to stay with this SAP NW version, you can simply implement SPNego for SSO to the Portal. See the SAP Note: 1488409 - New SPNego Implementation
AD password reset service is available with the SAP Identity Management product. See, more details here: SAP Identity Management 8.0 – SAP Help Portal Page
Regards,
Donka Dimitrova