Guvnor meant for business users?

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    Hello All,
    We are evaluating Drools for our production implementation  with special focus on the fact that it would let less technical people be able  to work effectively with business logic (once developers provide them with a  data model). We are relatively new to Drools and our impression has not been too  good specially around Guvnor (given that DRL is meant for developers and DSL is  nothing but a simple extension for DRL which business analyst won't be able to  use). Has anyone here used Guvnor or DSL effectively for a reasonable size  implementation?
    With Guvnor we are facing some issue which are very basic and Guvnor comes  across as a immature web application from the UI perspective (Because of being  less user friendly, incomplete messages for error situations etc). Also, its  difficult to find help on some simple scenario like the following,
    We have a "Customer" class and a "Agreement" class with one to many  relationship. We are trying to build a simple rule that if an "Agreement" has  missed payment (indicated by a boolean inside Agreement class), mark that  "Customer" as bad customer by setting the boolean field inside the "Customer"  class. Its a simple scenario to be build in DRL but how to we implement this  under 'WHEN' and 'THEN' section in guided editor without using the DRL free  forms?
    Any thoughts or help in these matters will be really helpful. Also, if  there are some helpful links around Drools that would help getting started with  the implementation, that would be great!
    Thanks in advance.