自分用メモです。
Dim ADOST As Object
Set ADOST = CreateObject("ADOST.Stream")
With ADOST
.Charaset = "UTF-8"
.LineSeparator = adLF
.Open
.WriteText "aaa", adWriteLine
.WriteText vbTab & "bbb", adWriteLine
.WriteText "ccc", adWriteLine
.Position = 0
.Type = ad TypeBinary
.Position = 3
Dim byteData as Variant
byteData = .Read
.Close
.Open
.Write byteData
.SaveToFile {FILENAME}, adSaveCreateOverWrite
.Close
End With