function MemoryStreamToOleVariant(Strm: TMemoryStream): OleVariant;
var
  Data: PByteArray;
begin
 Result := VarArrayCreate([0, Strm.Size - 1], varByte);
 Data := VarArrayLock(Result);
 
 try

   Strm.Position := 0;
   Strm.ReadBuffer(Data^, Strm.Size);

 finally

   VarArrayUnlock(Result);

 end;
end;

function OleVariantToMemoryStream(data: OleVariant): TMemoryStream;
var
  ms: TMemoryStream;
  i, len, lbound, ubound: integer;
  buffer: array of byte;
begin
  result := TMemoryStream.Create;

  lbound := VarArrayLowBound(data, 1);
  ubound := VarArrayHighBound(data, 1);
  len := ubound - lbound + 1;

  if len = 0 then
    exit;

  SetLength(buffer, len);
  for i := lbound to ubound do
  begin
    buffer[i] := VarArrayGet(data, i);
  end;

  result.WriteBuffer(buffer[0], len);
  result.Seek(0, soFromBeginning);

end;