Hosted site does not support Auto Update for Safari Extension

I have written a Safari Extension that I would like to support with Auto updates using the built in features of safari. Saving the hassle of people continuing with using the old versions and also working out how to let people know there is an update.

I know how to do it. i.e using the manifest file...

But my website Host does not support MIME type application/octet-stream for this type of file download on its servers and I also use WordPress which does not allow the extension file wrapper (.safariextz) to be uploaded.

The file must not be zipped.

I am probably not the only one in this situation and wonder if anyone else has managed to find a way to get around these two limitations.