First of all, disable or uninstall AdBlock. Don't use Adblock Plus and AdBlock simultaneously.
You should be able to click the Adblock Plus toolbar icon and choose Options. I can't say for sure since there's no documentation page for Safari yet and I don't have access to a Mac.
Safari's options panel is rather limited, e.g. it doesn't support buttons and other rich UI elements. Once Apple changes that, we can address this issue.