how to get the value of a cell and not the cells formula

I am using Windows 2007 with Visio 2010 Premium and a VBA subroutine to manipulate the cell data.

My VBA code is not returing  the "value" of a cell which references another cell.

The VBA command returns  the "formula" in the cell. 

Visio shape cell is written as:

prop.Design_Element = sheet.2!prop.current_design_element

The value of prop.Design_Element translates to :   "Address_List"

I have tried many VBA command permutations including the following:

DesElm = vsoShape.Cells("prop.Design_Element").ResultStr(Visio.VisUnitCodes.visNoCast)    and

DesElm = vsoShape.CellsU("prop.Design_Element").FormulaU

At VBA runtime the command returns  DesElm ="sheet.2!prop.current_design_element"   rather than DesLm="Address_List"

What is the command to get the runtime value?

thank you