Hi
On your demo page the average figures were about the same as above, but I am not convinced these really mean anything in this situation because I can view the source and get these figures long before the 100+ files have finished downloading. I am guessing these are server side figures, of which i dont have a problem with on your demo or our code.
The problem is that we are waiting ages for these 100+ files to download before we can use the editor. On IE7 etc it downloads about 2 files and off we go (has the same average figures in the HTML).
Its almost as if IE6 is not caching any of those files at all!
For my 2 cents worth I think the problem is because you are now downloading all images and files via this load.ashx file which IE6 is not caching because it thinks its dynamic. Whereas before (V5.3) all images etc were referenced directly and downloaded once and cached.
However not sure how this helps.
Hope you have some ideas.