GetPrimaryKeyDictionary doesn't exists in System.Web.DynamicData

Hi! I have a problem with function GetPrimaryKeyDictionary (http://msdn.microsoft.com/en-us/library/system.web.dynamicdata.metatable.getprimarykeydictionary(v=vs.110).aspx) in System.Web.DynamicData. It doesn't exists in this namespace and for me this class is necessary to create an audit under dataclasses. Can you help me?