Updating Custom Profile Fields: how?

OK, I’m modifying the profile.php to include come custom fields. That works just fine. However, when you click on the update profile button, it does not update those fields. Essentially, I can view and edit my database and it does not create new database entries, (although I can manually add those in) but it will properly display an entry if I manually enter a value. This tells me that there is some function somewhere that sends these values to the database… I just can’t find it.

If anyone could point me in the right direction, that would be awesome.
Thanks,
~Nathaniel