Hi Aniket, using DevTest 9.1, I created a VSI specific transaction response having a 3 minute response and got it to work correctly.
I set a transaction's Think time to 3 minutes (3m).
Then, I deployed the service with 100% Think Scale to ensure the VSE honors the Think Time.
I tried a Webservice execution from DevTest and it timed out after approximately 30 seconds. I bumped lisa.http.timeout.connection=18000. Stopped and started Workstation again, but it timed out at approximately 30 seconds. Perhaps, Workstation overrode the timeout. Not sure.
I went to SoapUI and changed the timeout property on my HTTP call to 3 minutes and invoked the service.
SoapUI waited for 3 minutes and timed out.
I then changed SoapUI to wait for 190000 millis (10 seconds longer than my VS 3 minute wait). Executed same request and got a response at approximately 3 minutes 1 second.
So, I would surmise that the service running on my VSE honored the 3 minute delay before sending the response.
In terms of your configuration, I cannot say why you are not seeing similar results. I would verifying the VSI think time, make sure that the response that is being sent is the one you set to wait 3 minutes, ensure that your service is running at 100% Think Scale, and retest after setting the SoapUI timeout property based on your test requirement.
If you continue to have an issue, your next step would be to open a ticket with CA Support.
Good Luck, Joel