It looks very "natural." I would suggest a trim and perhaps tightening the plants into specific placements, but that is only a suggestion! Otherwise, your ludwigia cuba is friggin' awesome!
As far as U. Grammifolia, I would suggest that you find someone online (a store) that will ship world-wide. People here in the States have it, but may have trouble sending it to you. I would think that one of the Malaysian online shops might be able to help you, or you could try Aquabid.com.
Good luck, buddy!