Public Structure udtPartInfo
        Public udNumber As String
        Public ReferencedFile As String
    End Structure

    Sub Main()
        Dim drawDoc As DrawingDocument
        drawDoc = ThisApplication.ActiveDocument

        Dim baseSheet As Sheet
        baseSheet = drawDoc.Sheets.Item(1)

		if (baseSheet.Balloons.Count = 0) Then Return  ' There are no balloons on the drawing.
		
        Dim valSet As BalloonValueSet
        valSet = baseSheet.Balloons.Item(1).BalloonValueSets.Item(1)
        Dim drawBOM As DrawingBOM
        drawBOM = valSet.ReferencedRow.Parent
        Dim partInfo() As udtPartInfo
        ReDim partInfo(drawBOM.DrawingBOMRows.Count - 1)

        Dim itemColumn As Integer
        Dim i As Integer
        For i = 1 To drawBOM.DrawingBOMColumns.Count
            If drawBOM.DrawingBOMColumns.Item(i).PropertyType = PropertyTypeEnum.kItemPartsListProperty Then
               itemColumn = i
                Exit For
            End If
        Next

        For i = 1 To drawBOM.DrawingBOMRows.Count
            Dim drawBOMRow As DrawingBOMRow
            drawBOMRow = drawBOM.DrawingBOMRows.Item(i)

            Dim partDef As PartComponentDefinition
            partDef = drawBOMRow.BOMRow.ComponentDefinitions.Item(1)
            partInfo(i - 1).ReferencedFile = partDef.Document.FullFileName
			partInfo(i - 1).udNumber = drawBOMRow.Item(itemColumn).Value
        Next

        For i = 1 To drawDoc.Sheets.Count
            Dim currentSheet As Sheet
            currentSheet = drawDoc.Sheets.Item(i)

            Dim checkBalloon As Balloon
            For Each checkBalloon In currentSheet.Balloons
                Dim matchFound As Boolean
                matchFound = False
				If (checkBalloon.BalloonValueSets.Count = 0) Then
				  Continue For
				End If
                Dim valueSet As BalloonValueSet
                valueSet = checkBalloon.BalloonValueSets.Item(1)
                Dim checkFilename As String
                checkFilename = valueSet.ReferencedFiles.Item(1).FullFileName

                Dim j As Integer
                For j = 0 To UBound(partInfo)
                    If checkFilename = partInfo(j).ReferencedFile Then
                        matchFound = True
                        If valueSet.ItemNumber <> partInfo(j).udNumber Then
					'	   Trace.WriteLine(" -- Overriding value: " &  valueSet.ItemNumber)
                           valueSet.OverrideValue = partInfo(j).udNumber
                        End If
                        Exit For
                    End If
                Next
            Next
        Next
    End Sub