logging in to the user portal with e-mailaddress from AD/eDirectory (UTM9)

We are using UTM9 with the following Firmware version: 9.004-33
Is there any way to configure the authentication server to log in with the email field from AD/eDirectory/LDAP instead of the username? Can we define somewhere the query to use to log in ?
We prefer to use the combination email + password instead of the username from AD.