Code:
Private Declare Sub CopyMemory Lib "Kernel32" Alias "RtlMoveMemory" (pDest As Any, pSource As Any, ByVal ByteLen As Long)

Public Function DoubleToBitString(theValue As Double) As String
  Dim LongArray(1) As Long
  CopyMemory LongArray(0), theValue, 8
  DoubleToBitString = LongToBitString(LongArray(1)) & LongToBitString(LongArray(0))
End Function