SOCKS v5

Has anyone here had any luck making Firefox and/or Thunderbird work properly with a SOCKS proxy? I’ve got one running via PuTTY and it works great for AIM and SOCKScap. I can’t get the damn thing to work with IE, Firefox, or Thunderbird. It appears that the apps are attempting to do their name resolution locally, so they don’t know where to connect to…

Any ideas?