Thanks very much, I already figured out how to split the double word into two words. It appears that I don't need to split a word into a 6 and a 10 bit value for the moment, so I will let that rest until needed.
This is how I did it:

Code:
Private Function HW(lngInput As Long) As Integer
' returns high word (Bit 16 t/m 31) 
    HW = lngInput \ &H10000
End Function

Public Function LW(ByVal lngInput As Long) As Integer
' returns low word (Bit 0 t/m 15) 
Dim lngTemp As Long
Dim blnAddBit As Boolean
    blnAddBit = False
    lngTemp = lngInput And &HFFFF&
    If lngTemp And &H8000& Then
        ' prevent overflow
        lngTemp = lngTemp And &H7FFF
        blnAddBit = True
    End If

    If blnAddBit Then lngTemp = (lngTemp Or &H8000)
    LW = CInt(lngTemp)
End Function