For a workflow there are two key elements.
One is identification of the user.
The other is tracking the state of the form, or which step in the process it
is in.

With a web service you can identify the form user each time, as well as
lookup their emal address, manager, department, etc.

Then also have a field in your form which stores the state of the form.

In your case you would want to have several actions on your submit button
one to update the field to submitted or whatever you want to call that state
and then to email it.  if you email first then the copy they recieve will not
say submitted so make sure you get the order correct.
Then put conditional formatting on the section or field to hide if the
formstate field is not submitted or what ever.

If you would like to see some examples of workflow let me know.