This appears to be matching the JMS default timeout (30 secs). Let's wait for SMEs comment if that is expected behavior or not. Another question is, where to specify JMS timeout? I saw that in the code the default value is 30 seconds.
which has the value of 30 secs. This is used by SOJSpecSender class. In the code, this will be overridden by the value of SOJSpecConstants.JMS_WAIT_REPLY if that is set. Otherwise, the default value will be used.
just examine the invokeaxis2 activity, you will see all the logic regarding JMS setup and the related classes (part of 3rd party jar praxis2JMSTransport.jar shipped OOTB). In theory, if you modify invokeaxis2 to set the SOJSpecConstants.JMS_WAIT_REPLY option in the client setup step (for 7.2 step 7), it should work.