[otrs] CC recipients in AgentTicketCompose

Hello, When I receive a ticket from a customer and he/she has created the ticket with a CC recipient (using mail), then, if I answer that ticket with an external mail, CC recipient is not included in AgentTicketCompose (only customer that created ticket appears as recipient "For:". I have modified "Ticket::Frontend::ComposeExcludeCcRecipients" from "yes" to "no" and from "no" to "yes", but in both cases, CC recipient is not included. How I configure OTRS for that purppose? Thanks a lot!!