css aggregation

Problem: If the aggregated css/js file doesn't exist then drupal is loaded, looking for it; a 404 for the file is usually the result.
Solution: Have a lookup table pairing the old file to the new one, returning the new aggregated file in the process.

Create 2 menu hooks
file_directory_path() . '/css/%'
file_directory_path() . '/js/%'

I have been testing turning css aggregation on/off, i am using drupal 6.5 with a modified version of aboutpeople theme.

In either case, it looks fine in firefox.

But in ie, with css caching enabled, can not find the aggregated css file.

I think it would be nice to know exactly how css aggregation works, and maybe instead of a different file name each time, it creates one file that it updates, or deletes depending on css aggregation being on.