Get OutStream from MediaSet

Hi,

recently I tried implementing the drag'n'drop Extension from @Vjeko.
Currently I'm using Nav 2017 and I'm using the MediaSet data type for Pictures.
But when compiling the Editor says that the Variable "CREATEOUTSTREAM" does not exist.

RegEx := RegEx.Regex('data\:image/(.*?);base64,(.*)');
Match := RegEx.Match(DataUrl);
IF Match.Success THEN BEGIN
  MemStream := MemStream.MemoryStream(Convert.FromBase64String(Match.Groups.Item(2).Value));
  Rec.Picture.CREATEOUTSTREAM(OutStr); //This Row
  COPYSTREAM(OutStr,MemStream);
  Rec.MODIFY;
  CurrPage.UPDATE(FALSE);
END ELSE
  ERROR('Invalid data type. Image expected.');

Maybe someone can help me.