According to Frequent Asked Questions, you need a valid Bing Maps application ID in the BingKey.xml file to enable the Bing Maps as the basemaps. I follow the instruction of Online Help 1.1.1 to get a Bing Maps Developer account and tried with my account name and account ID. But none of them work: The 3 Bing Map basemaps appear in Basemaps gallery but the it's just a blank one in the web part if I choose one of them as basemap. So what is the Bing Maps application ID anyway and how can I get a valid one? Thanks!