changing thickness in the sheet metal folder

I'm trying to change the thickness and the radius of the sheet metal folder (not the sheet metal features inside the sheet metal folder). Consequently, the changes in the folder data will propagate to the sheet metal features hence why I'm doing it.  I tried the following code:

' Preconditions:


'       (1) Part document containing sheet metal part is open.


'       (2) Sheet-Metal feature is selected.


'


' Postconditions: Default bend radius value is doubled.


'


'-----------------------------------------------


Option Explicit





Sub main()


    Dim swApp                   As SldWorks.SldWorks


    Dim swModel                 As SldWorks.ModelDoc2


    Dim swSelMgr                As SldWorks.SelectionMgr


    Dim swFeat                  As SldWorks.Feature


    Dim swSheetMetal            As SldWorks.SheetMetalFeatureData


    Dim bRet                    As Boolean


    Set swApp = Application.SldWorks


    Set swModel = swApp.ActiveDoc


    Set swSelMgr = swModel.SelectionManager


    Set swFeat = swSelMgr.GetSelectedObject5(1)


    Set swSheetMetal = swFeat.GetDefinition


    


    Debug.Print "Feature = " & swFeat.Name


    Debug.Print "  Thickness (Before)  = " & swSheetMetal.Thickness * 1000# & " mm"


    


    ' Rollback to change default bend radius


    bRet = swSheetMetal.AccessSelections(swModel, Nothing): Debug.Assert bRet


    


    ' Double the default bend radius value


    swSheetMetal.Thickness = 50.8 / 1000#
    
    Debug.Print "  Thickness (After)  = " & swSheetMetal.Thickness * 1000# & " mm"
    
    ' Apply changes




    bRet = swFeat.ModifyDefinition(swSheetMetal, swModel, Nothing): Debug.Assert bRet


 Debug.Print bRet

End Sub

But for some reasons it doesn't work although Bret is true at the end. When I edit the sheet metal folder, the thickness value is not changed. Any help would be appreciated