The Hierarchical Tool HIT is a software tool for hierarchical modeling and performance evaluation of discrete event systems. Besides analytical and numerical solution techniques HIT provides the evaluation of models by sequential simulation. Here we present concepts for optimistic distributed simulation of HIT-models by partitioning them with respect to subhierarchies. The main goals of the concept being presented are the preservation of model structure even in lower levels of the realization (e.g. use of the process view of simulation throughout all levels of abstraction) and distribution transparency on the modeling level (homogeneous model specification for all solution techniques).