XML source mapping error

I'm trying to create an XML file (for the first time) from my .csv file in Excel. The end result will be an XML file that I can import into a merge document in Adobe InDesign. I created the schema and it worked except for one thing. One field is an image field. For InDesign, its field name has to be: @photos. When trying to add the schema file to the XML maps, I get an error message stating that "a name was started with an invalid character." It's referring of course to @photos and Excel won't load the file. Any suggestions on what to do now?