On a production or acceptation server that is possible. In your application.conf file you can add the following properties:
UploadedFilesPath = D:/MENDIX/Production/WEB-INF/uploadedfiles/ PublicUploadedFilesPath = D:/MENDIX/Production/web/uploadedfiles/
If you have downloaded the application.conf file from the wiki both lines are already in it at line nr: 87 and 95
All normal files that are uploaded will be stored in the folder UploadFiles
All thumbnail images that were uploaded with the image uploader will be stored in the PublicUploadFiles folder
It won't be possible to change the directory structure. The XAS expects all files to be stored directly in the uploadedfiles folder and not in a sub folder.