Sure you can store entity handles outside the engine. I use an array of handles in my C++ app that calls the engine DLL. As I said handles are nothing but long integers, so I dont know for what reason you are not able to store them or what you expect Conitec to fix.

If you think theres something wrong with handles, then Spirit is right you should post a bug report, but if storing handles is really one of the things that prevent you from finishing your MMOG, then it seems to me that you have not had much chances anyway. I'm no expert but if you want I can write you a handle storing function in 5 minutes.

Also, sending of entity updates only to close clients is certainly nice but I dont think that this prevents you from doing a MMOG either. When the world is divided in zones, the servers only send updates to entities in that zone anyway, and in no MMOG you would place the US and Japan in the same zone.