I don't know a sample that targets this need. I cabngive you a few words about a way that I followed in the past.
I mixed DSL and WF. I decided to not redefine all business process concepts. My solution drew a gateway betweem the DSL (and dsl tools) and the WF model. To accomplish this, I developed a custom service to publish information to wf and used the WF ModelService
to gather information from WF.
And to model process or rules, users are invited to use WF designer. I integrate it into my dsl solution by using wpf support now offered by dsl tools.