Safari adds extra extension to downloaded files

I've recently set up a site for users to share their GeekTool scripts. The problem I've encountered is when people download the .glet files for GeekTool. These are essentially text files containing all the details of the "Geeklet".

Safari renames the downloaded files with an extra extension, so they are .glet.txt. This means users have to rename them to .glet before they can double-click them to open with GeekTool. This isn't a problem with Firefox.

Some Google-ing revealed this support document detailing why this happens:
http://support.apple.com/kb/TA24293
but it doesn't have a solution apart from to rename the files once downloaded.

I get the impression that it is my server telling Safari that the files are text files, so I thought I might be able to stop this by adding/changing lines in my .htaccess file. I tried adding this line:
AddType application/octet-stream .glet
but this just makes Safari rename the files .glet.xml instead!

Any suggestions would be greatly appreciated.

Oh, and for any GeekTool fans, the site is http://www.macosxtips.co.uk/geeklets