My name is Raul Fernandez. I am a Phd and Software Architect. Although I am a newbie in the freelancer world, I have worked with UML since UML 1.1 until version 2.5. This is an interesting project related to modeling scenarios. I am an experienced information system developer and architect and I have worked as a team leader with C/C++, Python, Delphi and SQL, and several case tools like Rational Rose, Visio, ArgoUML, Visual Paradigm, StarUML and Enterprise Architects.
I have worke with both Data Flow Diagram (since Tom de Marco book and Rumbaugh's OMT, altough is not part of UML I think it is very useful) and Activity Diagram in UML 2.
How is your scenario? What kind of help do you need exactly? Which case tool do you use?
I am sure I can make your work in a few days.
But, I offer advice you for two weeks. It is not a hard work for me: I lije modeling.