Display First "Save" of Document in DocType?

Hello,

Is there a way to display when a DocType is first saved, rather than submitted?

Why?
I want to use Purchase Receipt to automatically record when an item arrives (the user will start a Purchase Receipt when the item arrives onsite) rather than when the Purchase Receipt has been checked and approved (submitted)
In the Purchase Receipt DocType the Date and Posting Time field will display the Date and Time of record Submission, not the actual date and time it was started.

Is there a way to achieve this?

Thanks,
Paul