Generally, you can do this using a modal time history analysis under dynamic study. Presently, Simulation does not have the capability to input an SRS (shock response spectrum). You have to input the raw acceleration data over a shock event instead. Time to compute is not as a bad as you might think, but, yes, the time step would have to be on order of 1/f, where f is the largest frequency in your SRS. I made an enhancement request to include the SRS some time ago, BTW.
Post-analysis wise, one looks for the stress highs over the entire event. That was pretty CPU intensive, if I recall.
If you have only the SRS, you can "recreate" acceleration data from it using some tools on the web. Might not be free, but www.vibrationdata.com has some insight to this.
Thank you very much for the info. I was skeptical about the SRS data as an input in Simulation. It would be great if your enhancement request goes through. I will do some research on converting SRS into raw acceleration to make it work. I appreciate your help.