danjal,
what operation are you performing that needs a callback?
There are equivalents for AsyncCompletedCallback, but it will depend on the operation performed. i.e.
DevForce2009: ExecuteAsync(IEntityQuery,AsyncCompletedCallback<EntityFetchedEventArgs>,Object)
DevForce2010: ExecuteAsync(IEntityQuery,
Action<EntityQueryOperation>,Object)
DevForce2009: AddAsyncSave<T>(AsyncParallelTask<T>,Object,EntityManager,AsyncCompletedCallback<EntitySavedEventArgs>)
DevForce2010: AddAsyncSave<T>(AsyncParallelTask<T>,Object,EntityManager,Action<EntitySaveOperation>)
You can find this information in the API documentation (installed with DevForce2010).
EntityFetchedEventArgs is now EntityQueriedEventArgs. You can also find this information in the Release Notes provided with DevForce2010, (Entities and the Entity Manager >> Entity Manager >> Miscellaneous Changes) which is installed with DevForce2010.