For the first issue, you might be able to fix this by re-building the server-side of the BWCheck example and change the module function checkBandwidth name to _checkbw. Or the vice versa, change _checkbw in the player to checkBandwidth
http://community.wowza.com/t/-/31
You will probably also have to reconcile onBWCheck and onBWDone with the client-side code.
On the silverlight issue, not sure. It is switching, so that’s good. But as far as it not doing what you expect, I’m not sure. But you might be making assumptions about your bandwidth that are not actual from the point of view of Wowza server’s connection to you.
Richard