[otrs] Character sets

Hello; OTRS is *some* piece of work! We usually use ISO8559-1 around here, some people use UTF-8; is there a simple way to have OTRS automatically convert incoming mail (piped through the PostMaster-skript from a .qmail file) to a given character set, say ISO8859-1? This is to avoid getting: "This message was written in a character set other than your own.If it is not displayed correctly, click here to open it in a new window." at the top of every "external" message. (OTRS 1.3.1) -Joaquim