Many thanks for your reply
I know that every sane person would use the range header element instead of appending some parameter to the URL itself, but it's the only option I can think of when the requesting application (not necessarily a web browser) may not use the range header element at all.
I wouldn't be too surprised if that's how streaming content into a flash application has actually been like this for years now.
I'll probably try to get around this by setting up a wrapper PHP script, but it would even be better without all that clutter on a small and tidy HFS server