Change order of default reg. fields & email as username

[giovanni_gon]

Hello,

I'd like to change the order of my registration fields on s2member.

By default, the fields are (in this order):

username
email
password
strength of password
Custom fields

I'd like to do the following:

First Name
Last Name
Email
Custom Fields
password
strength of password

No username as I would like the username to be the email address.

Thank you in advance.