You can do what you want out of the box. I have the following fields in my Contact 7 Form:
FIRST NAME
LAST NAME
COMPANY NAME
EMAIL
TELEPHONE
MOBILE
MESSAGE
And I assign each of the above to the following in CRM:
FIRST NAME
LAST NAME
COMPANY (Which goes nowhere that I can see)
EMAIL
TELEPHONE
MOBILE
NOTES
To see the message you need to EDIT customer and scroll down to NOTES and you will have the original message that was sent when the person filled in the form.
