[TrumpetBlast]

The key is to work up to time alone. Leaving for very small increments at a time will become more secure that you will return. I'm talking twenty seconds to begin with, then coming back. Then slowly working up to a minute or two. It's so important that you don't come back in the door when he's crying or carrying on, else he will equate his behavior as productive.
I don't think vizslas ever like being alone, but they can learn to adapt. Like BellaVT mentioned, a lot of it has to do with maturity.