Custom condition on requestors change of a new ticket

Hello!
I am not very familiar with perl and now I have a problem to let RT
react on a requestors change of a new ticket.
I am not able to define the condition in a scrip to let RT send a mail
to the new requestor of a ticket with the status 'new’
Thanks for all your help in advance.
Eberhard

Eberhard M�hlfeld
ISV m.b.H.
Am Treptower Park 75
12435 Berlin

Tel.: +49 30 53433414
E-Mail: support@isv-gmbh.de