The Health Connection Engine should work on Vista for testing purposes, but we never tesated that configuration. You might have better luck building a VPC.

HCE supports the exchange of any kind of message, including HL7 v3. HCE does not have a dependency on HL7 v3. The two are complementary. HCE will take care of all the transmission. Use the article if you are required to implement the HL7 v3 standard separately from HCE.

Yes, you need the Normative Edition to study the HL7 v3 standard and understand how it works. You do not need it if you're using HCE and somebody else is giving you pre-constructed HL7 v3 messages. I any case I suggest having a look and getting familiar with the content.

A ballot is the process by which proposed changes to the HL7 standards are incorporated into the standard itself. You probably do not need to be concerned with this.

Good luck building an HIS :-)