I am trying to change a  ConfigurationName in a LibraryFeature.

this my code:

Dim swApp As SldWorks.SldWorks
Dim swModel As ModelDoc2
Dim boolstatus As Boolean
Dim longstatus As Long, longwarnings As Long
Dim swSelmgr As SelectionMgr
Dim swLibFeat As LibraryFeatureData
Dim swFeat As Feature
      Sub main()
  Set swApp = Application.SldWorks
  Set swModel = swApp.ActiveDoc
swModel.ClearSelection2 True
boolstatus = swModel.Extension.SelectByID2("Point56@Sk_Segment", "EXTSKETCHPOINT", 0, 0, 0, False, 0, Nothing, 0)
boolstatus = swModel.Extension.SelectByID2("Plane_Seg", "PLANE", 0, 0, -0.02, True, 1, Nothing, 0)
boolstatus = swModel.Extension.SelectByID2("Line35@Sk_Segment", "EXTSKETCHSEGMENT", 0#, 0#, 0, True, 2, Nothing, 0)
swModel.InsertLibraryFeature "K:\China Library Featuers\WIRE GUARD\Tube_Segment.sldlfp"
boolstatus = swModel.SelectedFeatureProperties(0, 0, 0, 0, 0, 0, 0, 1, 0, "segment4")
  
  Set swSelmgr = swModel.SelectionManager
 Set swFeat = swSelmgr.GetSelectedObject6(1, -1)
   Set swLibFeat = swFeat.GetDefinition
  swModel.EditRebuild3
  
 swLibFeat.AccessSelections swModel, Nothing
  
 swLibFeat.ConfigurationName = "40X40X15"
boolstatus = swFeat.ModifyDefinition(swLibFeat, swModel, Nothing)
swLibFeat.ReleaseSelectionAccess
swModel.ClearSelection2 True
End Sub

the Red words can change the LibraryFeature ConfigurationName ,but the size is wrong. The Right size is 40(not 80).

my code is wrong ?help me