OK - we can do this
xls is going to be enabled as a valid attachment type but the newest file format for excel is .xlsx and these cannot be loaded. If anyone is running this version they will need to save their spreadsheets in the older format (which they can do).
Another option is to load these to other hosting services (box.net
) and then just post a link to them or use Google spreadsheets
and make them globally sharable.