drupal6 default_settings subtheme

Hello World : )

I'm experiencing a lot of problem customizing my own subtheme with Zen-6x-1.0 because of the defaults theme settings overriding the subthemes ones .

Apparently (googling around ...) this problem seems to be already known but i can't find a clear solution to either disabling the default settings or the subthemes parameters ....

Any tips, links or info will be much appreciated