Here's a little longer answer, from one who has das svelte insides somewhat exposed today -- undoing carelessness of former owner. The shutter mechanism itself is replaceable if you reeely need the security and don't mind the hassle. Ronayers.com's microfiche shows the item, part 37155-14G00, for $76. Appears to include four (!) slide-onto-the-key-head plastic magnet-containing thingies, all matched to that particular shutter mechanism. Of course, after you fiddle with removing and replacing the enclosing plastic layer to get at the problem area you will want the extra keys themselves. Blanks to accomodate those plastic shutter-actuator slip-ons, are another $15 each at Ronayers.
Which is to say, bottom line, that you'll have a much easier time getting a mortal key (one that is just a key). I believe that more or less garden variety Suzuki key blanks have the same grooves your Burgman wants, but the shaft isn't long enough to allow the push-and-turn opening of the seat. My local dealer ground down the key blank's shoulders a little. Works fine, about $3 out the door.
