Andreas,
With Creo Simulate 2.0, you will have to make two seperate runs to obtain the desired pre-load. Creo Simulate 3.0 has a check-box to account for stiffness (shown below), and the operator doesn't have to manually make two seperate runs to obtain the desired pre-load.
I've attached a couple of documents to show you how to get the right pre-load using Creo Simulate 2.0. The fastener analysis tool is not a substitute for multi-body contact of fasteners in holes, as there is really no contact between the "bolt shaft" and the bore.