AutoCAD - Problem detaching XREF with ObjectDBX library

Using the following VBA code with ObjectDBX Library, it seems impossible to detach (or delete) a XREF block from the Blocks collection even after having previously deleted all the references to the block. Has anyone any idea or suggestion?

2) After having removed the references with this code, opening the file in AUTOCAD removes the block from the blocs collection!!! (but not re-opening it with ObjectDBX Library!)

Sub DetachXrefTest()
    Dim oLayout As AXDBLIB.AcadLayout
    Dim oBlock As AXDBLIB.AcadBlock
    Dim oRef As AXDBLIB.AcadExternalReference
    Dim oEntity As AXDBLIB.AcadEntity
    Dim vFileName As Variant

    Dim ODBX As ODBXClass

'*** SUMMARY of ODBXClass also usable in all VBA interface (EXCEL VBA, WORD VBA,...) *******
'
'Private AxDbDoc As AXDBLIB.AxDbDocument
'Private AcadApp As AcadApplication
'Private AcadWasNotRunning As Boolean

'Private Sub Class_Initialize()

'    On Error Resume Next
'    Set AcadApp = GetObject(, "Autocad.Application")
'    If Err <> 0 Then 'AUTOCAD is not running
'        AcadWasNotRunning = True
'        Err.Clear
'        Set AcadApp = CreateObject("Autocad.Application") 'Run a new instance of AUTOCAD
'        AcadApp.Visible = False 'Make it not visible
'    Else
'        AcadWasNotRunning = False
'    End If
'    On Error GoTo 0
'    'Get interface object for all ObjectDBX functions and link it with the
'    'AcadApp instance
'    Set AxDbDoc = AcadApp.GetInterfaceObject("ObjectDBX.AxDbDocument.17")
'
'End Sub

'Private Sub Cleanup()
'    On Error Resume Next
'    Set AxDbDoc = Nothing
'    If AcadWasNotRunning Then
'        AcadApp.Quit
'    End If
'    Set AcadApp = Nothing
'End Sub

'Property Get Application() As AcadApplication
'    Set Application = AcadApp
'End Property
'
'ALL ORIGINAL PROPERTIES AND METHODS ARE THEN OVERWRITED AS FOLLOW
'
'Property Get Blocks() As AXDBLIB.AcadBlocks
'    Set Blocks = AxDbDoc.Blocks
'End Property
'
'Public Function ObjectIdToObject(ObjectID As AXDBLIB.LONG_PTR) As Object
'    Set ObjectIdToObject = AxDbDoc.ObjectIdToObject(ObjectID)
'End Function
'
'Public Sub OpenFile(FileName As String, Optional Password)
'    Call AxDbDoc.Open(FileName, Password)
'End Sub
'
'ETC.....
'
'******** END OF SUMMARY OF MY ODBX Class **************

    On Error GoTo ErrHandler

    Set ODBX = New ODBXClass

    vFileName = GetOpenFilename(HWND, , "Fichiers Autocad, *.dwg", , "Sélectionner un fichier", , False)

    If IsArray(vFileName) Then

        ODBX.OpenFile (vFileName(0))

        sXrefToRemove = "Name of the XREF to Remove"

        For Each oLayout In ODBX.Layouts
            For Each oEntity In oLayout.Block
                If TypeOf oEntity Is AcadExternalReference Then
                    Set oRef = oEntity
                    If oRef.Name = sXrefToRemove Then
                        Debug.Print "Deleting "; oRef.Name
                        oRef.Delete
                    End If
                End If
            Next
        Next

        'At this point no error occured but block sXrefToRemove is
        'still present in Blocks collection

        'Trying to remove it...
        ODBX.Blocks(sXrefToRemove).Detach '=> ERROR: method detach of object 'IAcadBlock' failed
        GoTo SubExit

        'Other possibility but with same result
        For Each oBlock In ODBX.Blocks
            If oBlock.IsXRef Then
                'Debug.Print oBlock.Name
                If oBlock.Name = sXrefToRemove Then
                    Debug.Print "Detaching "; oBlock.Name
                    oBlock.Detach 'Same result at this line
                End If
            End If
        Next

    End If
SubExit:
    Set oBlock = Nothing
    Set oLayout = Nothing
    Set oEntity = Nothing
    Set oRef = Nothing
    Set ODBX = Nothing
    Exit Sub
ErrHandler:
    Debug.Print "ERROR: "; Err.Description
    Resume SubExit
End Sub