[otrs] Phonecall action always mentions customer

All, When placing an inbound or outbound phonecall, the from/to is always displayed in OTRS as the customer. Even when I receive or make a call from/to someone else, OTRS suggests in the phonecall action that it's the customer who is involved. Setting Ticket::Frontend::AgentTicketPhoneOutbound###SenderType to 'agent' does not make a difference. Can this be resolved? Thanks, Sander