Dominique,
My username/password is valid. The problem was I changed "requestip" to my actual ip address. Once I left that alone and only replace my username/password, a token was generated. I was able to load the map in Silverlight using this token. Sorry for the confusion.
My assumption is that token generated this way is bound to the ip and won't work if the map request is sent from a different IP? Do you have any theory why the token generated using referer=MyToken won't work? If it works, it should be more flexible.
Thanks!
Yukun