Tell-a-friend(s) at registration

[miner2049er]

(1) At registration (not after or later), how can I incorporate some text fields (say three) that a new user can (optionally) type in the email addresses of friends they would like to tell about my forum?

(2) And then, if any of these fields are filled in, vbulletin will automatically send an email to these friends with details of the forum.

(and set a DB flag indicating that emails were sent to these addresses.)

Or if (2) not possible, then just (1) and it allows me to access the forum DB, send out pending emails to friends, and then set an email sent flag in the DB

Wayne Luke, of the vBulletin team advises me to:

1) Add custom profile fields and set them to show at registration.

2) This would require custom coding which should be requested at vBulletin.org.

Having not hacked any vB PHP files yet, if I was to code this myself:

In what vbulletin PHP file, and at what position in that file, would I check for the custom profile fields containing data, and then send out emails?

Any advice appreciated - from either those who could provide the modifications, or those providing answers to my DIY option.

Miner2049er.