Looks like your little one 'loved' that beach - which makes it the perfect place to scatter his ashes. I am from Hawaii and have gone to many memorial services and the ones at the beach have always been the most peaceful for me - it seems that whenever I go back to those spots I can feel their spirit - so much better than a graveyard or crypt.
You are in my thoughts and prayers as you do your memorial and let go of your little love. He will always be there in spirit for you and I'm sure he would want his momma to be at peace