[otrs] CustomerTicketZoom article sort order

Hey guys, please give me a hint on how to change the sort order of articles in CustomerTicketZoom. For AgentTicketZoom there is a sysconfig option called Ticket::Frontend::ZoomExpandSort, which has no effect on the customer side. Our customers want to have a reverse sort order so that the newest articles are the first ones. Changing the source code would be fine aswell, but until now I wasn't successful in finding the corresponding code parts. Regards Jens