InfoPath Dev

It's been a very long time since I had to add a "Submitted Date" column in a SharePoint library from an Infopath form. Can someone remind me how this is done? I can see it in other forms I've created but I can't remember where it comes from or how I got it there. :/ This is a good field to have because you can 'hide' the "Submit" button if you don't want anyone to re-submit your forms, based on when the form was submitted using the following formula:

if submitteddate is less than now(), hide this control

Thanks

Wait, I figured it out. Just create a read-only text field and name it "SubmittedDate" and enter "now()" as the value, then click your submit button and add the rule that is "if the SubmittedDate is less than "now()", hide this control. Duh... LOL