In order to get a user friendly higher level of personalization, would it be possible to have a personalized message sent to the customer by the MP when an item is sold in spite of just an invoice ? i-e a field already written by the MP store owner and sent by the MP when a sale occurs..
Example :
"Thank you for buying XXX; You can contact me at ZZZ in case you need any further help."
or
"Thank you for buying XXX. Just type on this link to get all the similar objects from my store. Enjoy !"
etc.