I got a response about this from Engage.  It's not possible to easily work with the submitted values, http://www.engagemodules.com/Forums/f....  Based on this response, it appears possible to get to the form values by querying database tables directly.  I haven't played with it to figure out if the key is available somewhere in the querystring or post variables that will make it easy to identify the fields in the database.  
I expect the key info is not available either.  Since I haven't played with it, I'm not sure about the details of extracting the fields in the database table.  It would be helpful to note those here if anyone is familiar.