Is it possible to have an email address be required when a user creates an account on a B2B site?

PRESSERO > *Pressero FAQs
The only conditions under which an email is *not* required when creating an account is if all three of the following are true:
1)  The site is a B2B site.
2)  Allow Self-signup is turned on.  (This setting is found in Sites > [site name] > Settings > General Info tab in the Site Basics section.)
3)  Require Username for Self-Signup is turned on.  (This setting is found in Sites > [site name] > Settings > General Info tab in the Site Basics section.)
 
If you need the users to provide an email address for self-signup, then turn off "require username for self-signup."