You cannot get an OpenAccessContextBase from an ObjectScope. Both are wrappers around a lower layer object. But what you can do is use the following code to create an instance of a type.
var persistentTypeDescriptor = scope.PersistentMetaData.GetPersistentTypeDescriptor(typename);
var instance = persistentTypeDescriptor.CreateInstance(idValue);
If the id value is backend calculated you can pass a 'null' value.
The above code essentially does the same thing as MetaPersistentType.CreateEntityInstance.
OpenAccess ORM Q3 2013 simplifies your model operations even further providing you with greater flexibility. Check out the list of new features
shipped with our latest release!