Since this thread appears to be concluded, it's probably safe to hijack now.
Has anyone figured out what makes IE5 tick in terms of 404 pages? I cannot find any consistency on my own sites in terms of when my 404 page comes up and when IE5 displays it's generic white anti-sleuthing page. I read something about it depending on the size of your 404 page (i.e. if it's too small, IE5 will use its own), but that doesn't seem to have any effect. Any ideas?