In this paper we introduce a new modeling tool for constraint handling in the area of workflow technology. The constraint handlers can be used to improve the quality of business processes but without changing already existing business logic. Todays workflow languages provide no possibility to model constraints and the actions in case the constraints get violated explicitly. Fault and event handling mechanisms to react to events not expected in normal executions are only provided by the BPEL language. Using BPEL as workflow language we integrate the constraint handling extension without changing any existing semantics in a smart way. In our approach we use this fault and event handling mechanisms to extend the BPEL language with a constraint handling mechanism. By integrating this constraint handling tool into the BPEL language we provide an approach for quality driven process modeling with the BPEL language.