It should work when you connect them together. It does not matter what version it is. For your V4.5, you should choose "Others" and connect it with your other version using the appropriate settings. May I ask how you are physically connecting them? Your surroundings also affects the connection process because of the infre-red connection that Tamagotchis use to connect. Try to not connect in direct contact with the sun. If you find yourself still not able to connect, I suggest for you to refer to your V4.5's instruction sheet and see what it says on connecting with other versions to see if you are doing it right, but from what I am hearing from you, you are doing it correctly.
//Tamapal3000