We recently switched from a Nortel system to Mitel VOIP and analog system. In one of our conference rooms we have a polycom soundstation 2. When we try to use the conference feature it does not work. We dial the first party, hit conference, get dial tone, dial the second person, hit conference again and get dial tone. It used to join the callers. Hitting the "join" softkey does not work either. I thought it was a feature code, *4 but that fails as well. Is there something in the Mitel analog system I need to set? Not sure what the problem is here. Thanks.