Mitel with 5448 Keypad

I have deployed some Mitel 5215 and 5220 Phones. The 5220 have a 5448 K/pad that contains 48 keys. I was wondering if somepne could help me in getting to do line apearances. In other words tell me which extensions are bussy, or on the phone. It;s my understanding from very limited resources, that you need some XML scripts ? Can anyone send or point me in the right direction, please … Much appreciated and thanks for the support in the past.