ServiceDesk Active Directory sync with email field blank

Is there a way to set a standard template to populate an email address during an Active Directory sync where the field is left blank. For example, a network account is created in Active Directory, but the person who created the account doesn't enter an email address into the field. ServiceDesk will run the sync, and add the email address as the network account. (ex: jbob@domain.com)

Is there a way to set it so, when the email is left blank, it will add the email address as first name/last name@domain.com? (ex: joebob@domain.com)

Thanks in advance,

Steven B.