How to populate "User Principal Name" during user account provisioning?

From ActiveRoles

1. Configure and apply "User Logon Name Generation" policy in ActiveRoles Server. With this policy you can generate uniqueness value of the "samAccountName" attribute for newly created user account.
2. Configure and apply "Property Generation and Validation" policy in ActiveRoles Server. With this policy you should generated a value of the attribute "Logon Name" by the following rule:

RULE: 'Logon Name'  
  must be '%<samAccountName>@MyDomain.com' (default value)
  Upon object creation, this policy generates default value: Yes