Stop preloader from appearing for cached items

How do you guys do this?

I have a master file that loads in external swf’s and I’m showing a preloader during loading.

This all works great until the items have been cached by the browser and then the movies still load but the preloader doesn’t get time to animate and just shows for a split second which looks a bit crap.

I read somewhere about creating an array to store the paths of all the loaded in swf’s so I could then turn on and off the preloader’s visibility if that file had been loaded before.

This all worked great until I refreshed the browser window then of course the array got reset so all my stored values went and the preloader started to show its self again.

Then I thought could I store the array values in a local shared object but then I thought there’s got to be an easier way.

What is the best way of doing this?

My preloader is just a bog standard 100 frame animation that go to and stops the frame of the percent loaded.

Thanks in advance

Ricky55