From what I can tell, this mod replaces San Andreas' map to what is called 'Myriad Islands'. The only current way to do this is to script the models and load them client-side but the download would be far too large and MTA's streamer wouldn't handle it. MTA cannot replace SA's map either. This was already suggested in the past with GTA: United, it is not currently possible but could happen some time in the future.