HTTPS Container Field Download Error - data.file cannot be found ( Internet Explorer IE )

[GouldyFTW]

To summarise the problem, we have deployed part of our solution in IWP using HTTPS and have a problem downloading any file from a container field using Internet Explorer versions 7 & 8 (the other common browsers are fine).

When clicking into a container, the file download appears to start and then you get an error stating that "data.file" cannot be found.

I've been searching around the Internet looking for a solution to this problem - I've found a couple of threads, but found nothing useful. (you may find my posts at the bottom, before I decided to try and amalgamate the threads here).

http://fmforums.com/forum/topic/56723-iwp-pdf-downloads-over-https-fail-in-ie7/

http://fmforums.com/forum/topic/67123-internet-explorer-could-not-download-pdf-in-container-field/

http://forums.filemaker.com/posts/d6404f1366 (between myself and FileMaker support).

Any ideas on this would be greatly appreciated, if I can find or hear a solution, I will post the answer (or a link) in this thread.