在Lion中禁用webview的橡皮筋滚动

I have a Cocoa webview, with a web application in it. The web application has a fixed toolbar itself, and with the elastic scrolling, and the toolbar coming below the top, it looks bad. Is there a way to disable the elastic/rubber-band scrolling, or at least keep the toolbar from moving with the rest of the content? I can modify the web app as much as neede.I have a Cocoa webview, with a web application