Splitting STEP files in sub parts

HI. I'm using OCC 6.2 .net wrapper.
My goal is to load a STEP file and split it into several STEP with model structure.
The problem is that i don't know how to get the original part names:
The model structure is ok but all names changed in : "Open CASCADE STEP translator 6.2 8 xxxx" .

Here is the sub i use to read the main step file
Dim r As New STEPCAFControl.Reader

r.ReadFile(_fromFile)
r.Reader_.ClearShapes()
'MDTV-CAF
Dim D As New TDocStd.Document(New TCollection.ExtendedString("MDTV-CAF"))
r.SetNameMode(True)
r.SetColorMode(True)
r.SetPropsMode(True)
r.SetLayerMode(True)
r.SetMatMode(True)

If r.Transfer(D) Then

Dim ROOT As XCAFDoc.ShapeTool = XCAFDoc.DocumentTool.ShapeTool(D.Main)
Dim Colors As XCAFDoc.ColorTool = XCAFDoc.DocumentTool.ColorTool(D.Main)
Dim labels As New TDF.LabelSequence
Dim labelsCols As New TDF.LabelSequence
ROOT.GetFreeShapes(labels)
Colors.GetColors(labelsCols)
'ROOT.GetShapes(labels)

For ic As Integer = 1 To labelsCols.Length
Dim labelc As TDF.Label = labelsCols.Value(ic)
' MsgBox(GetName(labelc))
Next
Dim tn1 As TreeNode = Nothing
Dim tn2 As TreeNode = Nothing
Dim ts As syShape = Nothing
Dim nRoots As Integer = labels.Length
For i As Integer = 1 To nRoots
Dim label As TDF.Label = labels.Value(i)
' MsgBox(GetName(label))

If XCAFDoc.ShapeTool.IsAssembly(label) Then
Nodi.Text = GetName(label)
recurse(label, Nodi, Colors, r)

Else
MsgBox("nessun assieme trovato")

End If

Next
End If

here is the sub that recurse the structure

Public Sub recurse(parentLabel As TDF.Label, tNode As TreeNode, Colors As XCAFDoc.ColorTool, r As STEPCAFControl.Reader)
'Dim parentLabel As TDF.Label = node.Father.Label
Dim Livello As Integer = 0
contaParent(tNode, Livello)

If parentLabel.HasChild Then
Dim nodeIterator1 As New TDF.ChildIDIterator(parentLabel, XCAFDoc.General.ShapeRefGUID(), True)
While nodeIterator1.More
Dim node1 As TDataStd.TreeNode = CType(nodeIterator1.Value, TDataStd.TreeNode)
Dim questo1 As XCAFDoc.ShapeTool = XCAFDoc.DocumentTool.ShapeTool(node1.Label)
'Dim labels2 As New TDF.LabelSequence
'questo1.GetFreeShapes(labels2)
Dim Shp2 As TopoDS.Shape = XCAFDoc.ShapeTool.GetShape(node1.Label)
Dim tn2 As New TreeNode
If Not Shp2.IsNull Then
'Dim appo As String = tNode.Parent
Dim ts As syShape = Me.addSyShape(node1.Label, Shp2, Colors, Livello, r)

tn2 = tNode.Nodes.Add(ts.Id, ts.Name)
tn2.Tag = ts
tn2.ToolTipText = CType(tn2.Tag, syShape).Id

End If
If node1.HasFather Then
recurse(node1.Father.Label, tn2, Colors, r)

End If
nodeIterator1.Next()
End While

End If
Dim theFileName As String = IO.Path.GetDirectoryName(_tmpFile) & "\" & thisShape.Name & ".STP"
'Dim w1 As New STEPControl.Writer(r.Reader_.WS, True)
Dim w1 As New STEPControl.Writer()
w1.Transfer(shp, STEPControl.StepModelType.AsIs, True)
w1.Write(theFileName)
End Sub

thank you

here is the sub that write the STEPs