helmet lock

I recently traded up, selling the 1997 R1100GS I’ve been riding since 2009 – my second BMW, following a brief stint on an F650GS Dakar – in order to pick up a little newer 2005 R1200GS. Despite having enjoyed riding the 1100GS, especially once I had picked up an aftermarket Wunderlich Ergo seat...

Hi there, Just got a 2007 R1200R and I am wondering which is the best way to lock my helmet (and sometimes two) to it There seem to be not a single pin under the seat for such purpose. I will appreciate anyone sharing their experiences with me. Thank you! Silvio.