Downloadable files on WAP sites

How do I get my smartphone's browser to download files?

[gibbergibber]

I'm working with a small Symbian software developer to create a site where people could download their apps straight onto their smartphone using the built-in browser. It's intended for people who don't like transferring stuff over bluetooth or memorycard (a surprisingly large number of smartphone owners).

A rival developer has a WAP site where you can click on a link and the application downloads onto the smartphone. This works on the smartphone's default browser, and it works really well.

When we tried to replicate this on our site though, we kept getting the following error message: "Unsupported content type"

What are we doing wrong? We even tried making a clone of the rival's site with the same WML code and the same file, just to see if it would work, but the same message appeared.

I assume there's some kind of settings on our website that need to be altered so that the smartphone can retrieve the file, but does anyone know what they might be?

The funny thing is, I have the NetFront HTML browser on my smartphone too and it downloads the files without a problem. Downloading is only a difficulty when I access our WAP site on the default WAP browser.

The file type in question is a Symbian .SIS file, and our site is on an Apache server.