Use a Master Lock Gun Lock 0.22" (5.6mm) dia., 14" (35cm) long armored cable with brass ends prevents scratches.
Can even hold my jacket as I had two grommets installed at the sleeves and I just run the cable through them.
Plus it can even lock your bikes rotor to the fork leg!
http://www.masterlock.com/product_details/GunLocks/107KADSPTWho needs more chrome crap hanging on the bike.