Visual Studio 2010 cannot add existing items as links

I'm trying to add existing files as links to a Website project in Visual Studio 2010. This is so they will get added as a reference开发者_StackOverflow rather than as a new copy of the file. VS2010 help says there should be an "Add as Link" choice on the open file dialog in the Add dropdown box. However, I only see an "Add" choice in the dropdown, which adds a new copy of the file not a link.

I must be missing something obvious here, but not sure what. Your help would be appreciated.

Website projects do not support linked items. This cannot be done from VS UI and attempt to do that from macro or using sdk will result in 'Webs do not support linked files.' exception.