Tested using 3.0 PR with my own Bing Maps Key and it worked fine.
対処法
1. Manually add the Bing Map key into config.xml after the style tag and add the Bing maps basemaps under the operationallayers tag (refer to screenshot - 5.jpg). <bing key=”yourkey”/><basemaps><layer label="Streets" type="bing" visible="false" style="road" culture="en-US"/> <layer label="Aerial" type="bing" visible="true" style="aerial"culture="en-US"/> <layer label="Aerial with labels" type="bing" visible="false" style="aerialWithLabels" culture="en-US"/></basemaps>2. Save the config.xml file and open the application in Application Builder.3. The basemaps will be listed under Selected basemaps in the BaseMap and Operational Layers dialog box.