From SSO 12.5 - 12.8, Access Gateway Architecture is Introduced.
How to Monitor SSO 12.8 CA Access Gateway?
Siteminder Secure Proxy Server / CA Access Gateway
APM for SSO 13.2
From SSO 12.5 - 12.8, Access Gateway Architecture is Introduced. And a built in EPAgent can be used to monitor SSP Access Gateway.
CA Access Gateway Architecture Introduced:
Data Monitoring Using CA Application Performance Management:
How do I install SPS/CA Access Gateway to work with EP Agent?
APM Agent for Secure Proxy Server: