Send auto email notifcation from users email not system notification email id

hi guys,
i wish to have a welcome email sent to customers whenever a value in the form is true… but the email has to be sent from the user who created the customer.

how can i do this ?

at the moment when i create a notification it asks to select n email id to be used to send th email notifcaiton and the notifcation is sent from that id only… this creat very much problem… as when customer replies to the email it goes to notifcation emil id rather then who created the customer