arcobjects - Can you programmatically change the button image for a ESRI.ArcGIS.Desktop.AddIns.Button?

I'm new to the AddIn customization model in ArcGIS 10 and I'm trying to figure out how to change a button image for a button. I'm looking for the equivalent to the BaseCommand UpdateBitmap method and haven't had any luck. Is this a limitation of the AddIn model? Or did I miss something obvious?

Answer

Ok, I've worked something out using ICommandItem.FaceID. I wasn't initially thinking of using ICommandItem, but it gets the job done.

ICommandItem commandItem = ArcMap.Application.Document.CommandBars.Find(...;
commandItem.FaceID = ESRI.ArcGIS.ADF.COMSupport.OLE.GetIPictureDispFromBitmap(bitmap);