I'm struggling with that too. Please see post http://social.msdn.microsoft.com/Forums/en-US/wfprerelease/thread/49d2aa2f-27bd-4c6c-a955-bfed7f6cbf74/#7f784d2a-12c1-4c21-b611-745fe9bdce67
Especially reply from Tim:
"There's a blog series I did on getting the most basic parts of ICompositeView working, however, it was hard slog, I didn't get very far, and there's lots of bugs, so I don't think it has been that useful to people looking for a simple solution. (sample
Second option is downloading the State Machine source code from codeplex and using that as a basis for your own custom flowchart. It is a complex sample code but full of features and much less buggy. Of course you don't have to modify State Machine if State
Machine already solves your problem. If you do want to modify it, or encounter bugs with it you might be able to get some support via this forum.
[A last ditch option for those who want to be broken by future .net releases that I have seen people doing is interesting hacks in designer, like modifying the visual tree directly.]
But in summary - there is no really easy way to add the custom flowdecision feature to flowchart.
State Machine 4.0 link: http://wf.codeplex.com/releases/view/43586
Besides this, I've seen something done in .NET 3.5 with FreeFormActivityDesigner which would've been very useful for me (see methods exposed) but it belongs to System.Workflow.ComponentModel.Design and
can't be used with .NET 4 activities and from what I see in post http://social.msdn.microsoft.com/Forums/en-US/wfprerelease/thread/dff6046c-b451-4ffc-b51d-137488c60617 the
approach recommended is WorkflowItemPresenter (see WF 4 samples).
Currently I'm studying the code from StateMachine, see how far I get but like Matt Winkler says "Our goal was to have
a robust, extensible freeform base that could be used to construct a number of different graph oriented workflow designers. Unfortunately, we will not have time to complete that for vs2010" (http://social.msdn.microsoft.com/Forums/en-US/wfprerelease/thread/dff6046c-b451-4ffc-b51d-137488c60617)
they didn't finish therefore not easy with VS2010.