How do I access the contents of the Relationships cell of a container?

[RichRif1]

I would like to use the contents of the Relationships cell of a container in a formula but when I reference it I get a TRUE/FALSE value rather than the actual content of the cell. When I open the container shapesheet, I can see the cell content and copy it to the clipboard...

Can someone explain to me how I can access the contents of the Relationships cell? Thanks in advance.

[Yacine]

Afraid, you'll need VBA to get the formula instead of the result.
http://blog.bvisual.net/2009/09/07/visio-2010-containment-and-cross-functional-flowcharts/

and some additional material
http://blogs.msdn.com/b/visio/archive/2010/01/12/custom-containers-lists-and-callouts-in-visio-2010.aspx
https://www.packtpub.com/books/content/understanding-shapesheet%E2%84%A2-microsoft-visio-2010
http://blogs.msdn.com/b/chhopkin/archive/2011/06/09/shapes-that-calculate-based-on-their-container.aspx
http://visguy.com/vgforum/index.php?topic=4411.0