[Plugin: Advertising Manager] Add sidebar ads to fit the length of the page?

Thank you for this great plugin. I’m currently using the “skyscraper” Adsense ad (120×600 pixels) in my sidebar, which works great for short posts and pages. However, with long posts the ads simply don’t cover the length of the page. So I have a an bunch of blank space on the side of my blog. I want to “fill in” this area with ads. Is there any way I can do this with my sidebar/widgets? Or any other ideas for how I could accomplish this?

example here: http://img217.imageshack.us/img217/5179/screenshotae.jpg

http://wordpress.org/extend/plugins/advertising-manager/