The images are held in a different repository and you are exporting them with the ultimate goal of uploading them to Scene7?
Scene7 doesn't allow duplicate names in the account. So you can use the uplaod setting of "Overwrite in any folder, same base asset name regardless of extension"
http://help.adobe.com/en_US/scene7/using/WS632224e4651bd421-61bec0251262f141d39-7ffe.html
Alternatively you can turn the overwrite settings off and Scene7 will create "imagename", "imagename-1", "imagename-2" and so on, which you can clean up later with advanced searches