clientaccesspolicy.xml in SharePoint online with Office 365

Question

Is it possible to place clientaccesspolicy.xml file into site root for the SharePoint Online, which is part of Office 365 subscription? The point is to use Silverlight CSOM from a Silverlight Application running in another environment (on-premise, or hosted). I couldn't find any solution for the clientaccesspolicy.xml. There are only work-arounds suggesting to combine the external (to the Office 365) Silverlight Application with a web/wcf/ria services, that would use the .net client object model to query the data.