There is a config which enables you to do that, have been a couple threads on SPUF about it, like this one.
hat's don't bother me... the unusual effects and bright paints however... some hats look good with paint but most (1 collor) painted hats just make you want to scratch your eyes out.
Watch the artwork of this video and you'll understand. [youtube]http://www.youtube.com/watch?v=h_c3iQImXZg[/youtube]