Custom Variables in Message Notification

When using the messaging notification in VitalPBX, we should have the ability to enter variables so the person can get info about the caller. For example, a doctor has an emergency mailbox on the system. He wants to be texted when someone goes to the mailbox. I should be able to text him the following: ${CALLERID(name)} from phone number ${CALLERID(num)} went to the emergency mailbox.