Actions > Create User Record: created a new user account no email has been sent, why?
I don't believe any work has been done to enable this so a patch to core would be required.

The workaround we have often used is described in this blog - basically it uses a civi tag, that triggers a drupal rule, which then uses drupal default processes for creating a drupal user and hence sends out the email etc.

We developed that approach for different scenarios and is probably overkill but it works so we use it ;-)