The Worflow of a creation form plugin goes something like this:
(A) Data is submitted -> Data is placed into the WP database -> Data is handled -> Sending a notification via email and/or placement in the SalesForce database.
Whereas work flow need to go something like this:
(B) Data is submitted -> Data is handled -> notification is sent via email and/or placed in the SalesForce Database.
The key is that data is never stored on the WP Database, only sent via email and/or stored on the SalesForce Database.