lap apron, etc.
I own a Scooter Skirt, which is very similar to the Corazzo Lap Apron. If you keep the speed down (ie., ride on city streets, not freeways), it works very well. It is quick and easy to put on, and it fits under the seat. On my Vespa 250, the leg shield is wide enough to keep it from flapping up at speeds below 60 mph. That is not the case with my other scooter, an Aprilia 500ie with a narrower leg shield. The Scooter Skirt flaps up on that bike. You can attach it to the cowls with velcro, though. And the owner of ScooterSkirt, Ruben, is a Modern Vespa member and really nice guy.
My favorite solution for both bikes is a pair of nylon overpants that have a waterproof liner for rain. I have a pair from First Gear that I like very much. They have a removable quilted liner. I can put them on or off in half a minute. I have the HT pants for winter and a mesh pair for summer.
http://www.scooterskirts.com/
http://www.firstgear-usa.com/fgweb2.nsf/Products/53C7465422C25AFB862571F0005C46B1?opendocument