I had tried to rely on the velcro tapes that the IL IPass folks provide, but one day, had the flippin' transponder jump/fall off. I got lucky that it went down into the bike and stayed on the engine mount bars for the 50 miles to get home.... But decided to afix the transponder more securely.
I had the mesh bag- even had suggested it in a post once upon a time(maybe on the Kawasaki Beartooth forum.)
I didn't like the bouncing around in the wind and that it still wouldn't stay flat (horizontal or vertical) even being behind my windshield. I don't think it read well all the time.
Since, I bought and mounted http://www.jjcyclepass.com/
and now have NO PROBLEMS. It is attached to one of my windshield bolts off to the side and is not the hindrance to viewing that I thought it might be at first.
Current Ride: '08 Kawa Vulcan 1500 Classic, [Jardine Pipes & Pass. Footboards, Kaw W/S & Lightbar, w/MS Lowers, Kawa Lg. Pass. Seatrest, Cobra Sm. Rear Luggage Rack, Cobra Highway Bars w/Pegs, RR Windswept Saddle Bags, Grasshopper Driver Backrest. M/C Ent. Front Fender Trim, Turn Signal-Running Light Mod. & Comagination Headlight/Taillight Modulators, LED Driving Lamps, SpeedoHealer, Steibel Horn, Phatrisers II, Kuryakyn Transformer Grips w/ Helmet Locks, Water bottle Holder, IPass Holder]