Ah, english is much better.
I don't think that what you want is possible in the Vista Security System in the way you think of it.
Nevertheless, while I was looking for some samples about WCF i came across an interesting article on Codeproject:
http://www.codeproject.com/WCF/AppWatcher.asp
I know, this is a .NET article, but he author uses a out of process
com+ component to start an application in the users context out of a service on a vista machine. The technology he used should be the same with a win/32 service.