InfoPath Dev

I am trying to create an InfoPath form library where users can fill the form out, save and continue filling it out at a later date, with the option to submit (starting a workflow).

I have tried using a data connection with submit button, but SharePoint also starts the workflow when a user saves. Is there a way to use the default save & save as option just to save, and the submit button to save & start the workflow?

What about adding a status field to the form (you don't have to show it on the form, but you'd want to promote it to SharePoint). Then, when the user "Submits" the form, you could use rules for the submit -- one could set that field to "Submitted", the other could submit the form to the form library... your workflow could be based off the condition that Status = "Submitted" ?