Chris, those rails are Ventura L brackets and can be used to mount the 50l bags to a custom A-frame rack [either onto pillion seat or on the rack or 2 bags zipped together]. or fit the grab rail which is in your kit.
I have them on my bike and it is a great luggage system if you don't want hard luggage, as you can remove the A-frame & bag in 30seconds and only have the rails left on the bike. Also the custom 50L bags are very stable and when fitted on the pillion seat they have no impact on high speed dynamics

. I rate them very highly
the L frames retail at about £90 and the grab rail at £20, so these are a bargain for someone
http://www.ventura-bike.co.uk/fitments/ ... storm.aspx
and with the luggage rack removed
