We are installing a Mitel 3300 with 5330 and 5320 IP phones. When making outgoing calls we are unable to HOLD or TRANSFER a call, those buttons do not respond. Incoming calls are able to HOLD & TRANSFER fine. The 3300 is connected via TIE line to a Nortel Opt 81, old release 23.55 using EM4 trunks. Any ideas appreciated.