Automatically set REMOTE_USER variable as EmailAddress for WebExternalAuto

Hi, I’d like to know if I can automatically set the users’ EmailAddress
when using $WebRemoteUserAutocreate? I want it to be the same as the
username (REMOTE_USER) variable.

I’m using RT’s external authentication to log in via an OAuth2 proxy,
which sets the REMOTE_USER=<email_address>. This is working fine and
user creation is enabled with $WebRemoteUserAutocreate. The problem is
if the email address of the user in not set they get an error “No
permission to display that ticket”, when submitting a ticket via the web
form, and the ticket is created with no requester.

I’ve seen there is an $AutoCreate variable but can this be used with a
user variable and, if so, which one?