Can I use the Silverlight Control or the REST Services with my existing Customer Services site account?
No. The new Silverlight Map Control and the new Bing Maps REST Services require that users have a new Bing Maps account which uses the new, lightweight method of authenticating. It allows customers to create up to five Bing Maps Keys for use in Bing Maps applications and to manage those accounts from one interface. To get started, visit the Account Management Portal.