How to get the exact value of lambda & tau for FTA Analysis

Hello,

I am using Windchill Quality Solutions 11.0 for FTA(Fault Tree Analysis).

My calculation type is Lambda Tau, to get the failure rate and time for it.

With this type, I can calculate the Unavailability(Q), which is probability of failure.

But what I really want to know the the failure rate(lambda) and exposure time(tau) of it.

I guess there might be way to get these values on FTA function, but I can not find it so far.

Please guide me how to get it with detail instruction.

Thank you.