The remote name could not be resolved: 'dev.virtualearth.net'The solution is easy;
Navigate to the webconfig file for the instance of Reporting Services you want to proxy out to the internet. Typically for 2008 R2 this will be:
<drive name>\Program Files\Microsoft SQL Server\MSRS10_50.<instance name>\Reporting Services\ReportServer\web.config
Add the following xml fragment to the file - I usually add it in-between the</runtime> tag and the </configuration> tag, at the end of the file:
<defaultProxy enabled="true" useDefaultCredentials="true">
<proxy bypassonlocal="True" proxyaddress="http://<proxy server>" />
Save the file.
This of course assumes your server is allowed to proxy out in the first place (which it will need for Bing maps integration). You can test this by logging onto the server and firing up a browser or by asking your friendly local sysadmin...