Starting a Interactive Process in Vista using TService

[OregonGhost]

While I still cannot imagine a situation where starting an interactive application from a service is necessary, I have three questions to this approach:

1. What happens if more than one user is logged on?
2. Where does the service get the user login password from?
3. What happens if the service does not run with full rights?

Oh, apart from the question what happens if services and user applications are even more separated from each other in the next version of the operating system