Variables for CS Generic Template SCC_TM_ASSIGNED Notification

I am trying to determine if/how we can add a value to the template variable options under PeopleTools > Workflow > Notifications > Generic Templates for use with the SCC_TM_ASSIGNED template for CS Task Management New Task notifications. The delivered Recipient Name variable results in the full name (first and last). One office has requested to use only student first name in these notification emails.

As best I can tell, the variables are defined in the app package SCC_TM_TASK_MGMT.NOTIFICATIONS.TMNotifications. Is that correct? Would we have to customize the app package to add a variable? Is there a delivered option for defining additional variables?