Hi moojjoo and sorry for the late reply!
Yes, you can get the returned ID. I assume you are using a "Submit" data connection in InfoPath, which makes it impossible to see the return statement unless you are using code to submit the data connection. If you want to add code, look at the .OutputLocation property on the WebServiceAdapter2 class.
Otherwise, you can convert your data connection to a "Receive" data connection (the first question in the data connection wizard), populate the queryFields with the appropriate information, and then the return ID will be underneath the dataFields node once the query has been issued.
The two data connections work exactly the same under the covers of InfoPath, but they are just handled a little differently by the designer and allow you to do different things with them.
Good luck!
Matt Faus / Microsoft InfoPath MVPQdabra® Software / Streamline data gathering to turn process into knowledge