Agree that the word “Smart” is thrown around too much… Also, the incoming smart string is used for EDI to auto POPULATE fields… BUT one thing to be careful of is that this does not force any “on-field-changed” code in those fields to be run.
So… pretending that there is no such thing as a smart string input, here is how I have done what you described. I would suggest that you pass the smart string via the line item description on the sales order. ie, you would enter the configurator part number on the order, then enter the smartstring into the description. THEN you would configure it.
Inside the On-Page Loaded, you would add some code to examine the line description, and if found, split it out into all the other inputs (without the need for the button)