[otrs] Subject without Ticketnumber (TicketSubjectClean)

Hello all, by searching a solution for building subjects in answers without Ticketnumbers, I found a sub called TicketSubjectClean. I'm not really fit in perl, but as far as I understand the code, it cleans out the Ticketnumber from the subject. Does anybody know where to activate this param? I'm using otrs 2.2.6 with ITSM 1.0.6 Thanks in advance