[GHRake]

An example that is working for me, I just copy and paste the original css below and rename them

In vbulletin-chrome.css:

#ad_global_above_footer {
	width:100%;
	padding:{vb:stylevar ad_padding};
	margin:{vb:stylevar ad_margin};
	text-align:{vb:stylevar left};
	clear:both;
}
#avt_global_above_footer {
	width:100%;
	padding:{vb:stylevar ad_padding};
	margin:{vb:stylevar ad_margin};
	text-align:{vb:stylevar left};
	clear:both;
}

And then in ad_global_above_footer I change the div id to match:
<div id="avt_global_above_footer">

aggresive adblock filters will filter by common ad image size so you can change the image sizes by 1 pixel length and width to bypass