(reposting fixed version here, sorry!)
You can try pasting the following code from siria's skin, with or without the extra comments, into the loction of your choice in your toolbars.cfg.
I changed the .bmp index number to zero because it doesn't seem to matter, the AuraAlpha(Large) privacy images are all identical! You can change the tooltip text in the third line ("Hide most Ad-Banners" etc.) to say anything you like.
I have no idea if this will work with your version as I'm not able to run it.
See skin for more info, such as flash options.
## AdBlock - HELP
## Ads are not really blocked, only hidden: always loaded, just not displayed if 'blocked' here.
## Press F2 -> Content Filters for more info on CSS-Ad-Blocking.
## Attention: This can never be perfect, and sometimes also hides 'good' images accidentally.
## The advertisement-definitions are in a text file, named "adblock.css" in the profile/chrome folder.
## To change it, open directly, or via menu: Edit -> Configuration -> AdBlocking Stylesheet
## To see the changes, toggle AdBlock on-off and reload page. No restart needed like with user-stylesheet.
## (own buttons), and to control all sorts of stuff: kb.mozillazine.org/Hostperm.1
Hide most Ad-Banners (could accidentally hide a 'good' image too). Right-click to modify detailed settings.