Either zip the file and then attach it or if you have file extensions show then change the .fit to .zip. Just remember to put in your post that you have changed the file extension. Then use 'Insert' at the bottom of the reply box, select 'Insert image/video/file', in the new box change 'From' to show 'File Upload', browse to the file and wait till it uploads, click on 'OK' and you should be good to go.
