Suresh,
Here's a related thread:
http://www.otmfaq.com/forums/f21/login-information-674/ (Login Information)
In short, OTM once had this capability, via a Servlet, to monitor which users were currently logged in, the total number of sessions and the memory related to those sessions. Unfortunately this broke in OTM v4.0 or v4.5 when we moved to a newer Tomcat version and was re-implemented.
So - your testing tool will be able to tell you accurately how many people are logged in and using OTM for Performance tests, but you won't be able to verify within OTM, or on a production system.
I encourage you (and everyone else) to submit these requests to Oracle in the form of Enhancement Requests (through Metalink), as OTM needs to mature from a management perspective to ensure it stays a viable and useful product.
Thanks,
Chris