Field confusion!

I’m trying to use the responsive classifieds theme. Having many issues with registration fields. I think it is only NORMAL to ask for a phone number and first, last names when registering someone. However, the default registration area does not have these. However, the based WordPress does have first and last name fields. If i add the custom fields first_name, last_name, and telephone to my registration screen, they do not update the information in the My Account details screen!! Also, there is a Telephone field in the My Account details area, however, it doesn’t seem to store a phone number anywhere. When i enter a basic phone number xxx-xxx-xxxx and save, i get no errors, but when i pull it back up, the Telephone field is blank.
Has anyone had any luck adding first_name, last_name and a phone number field to the registration area, and having it appear in the My Account details area?