Has anyone been successful in setting layer properties through the Set methods available under ESRI.ArcGIS.Client.Extensibility.LayerProperties class (http://help.arcgis.com/en/webapps/sharepoint/apiref/api_start.htm)? For example, I tried to use SetIsVisibleInMapContents and SetPopupTitleExpressions but neither works (not reflected on the map webpart) although the respective get methods return back the values that I set.