SPRibbon methods not available

Some time ago I was experimenting with the SharePoint 2010 ribbon. Basically I wanted to hide some out of the box ribbon buttons. Via the SPRibbon class in the Microsoft.SharePoint.WebControls namespace you can get references to the ribbon and do all kinds of stuff.

Now the problem was that I did not have access to all the methods I would expect to see. After some searching I found out that you not only need a reference to Microsoft.SharePoint.dll but also to Microsoft.Web.CommandUI dll. Once done, you will see all the methods.