i think that will not work
please see here
demo.joomlaaa.com/index.php?option=com_comprofiler&task=registers
i have used this plugin
demo.joomlaaa.com/joomla-community-builder-email-as-username-plugin.html
to hide the username and make it = email address as there will not be two identical email address so there will be no duplication or u can make a hack to your cb register form

I have enable email as user login, but that means that the users have no idea what their username is! Which is difficult when asked to input their username in the lost password page!

Help!

username will be the same as the email

I bought this product and never got it. An error came up when purchasing and the company that handled the payments could not get onto the company I paid the money to. Anyone know of an alternative?

i have sent it to all users who bought it
sorry for the delay