This what I did to get all the planets to work in the game that comes with the mod.
This is a strange way to do it but it works. Do this with a seperate folder so you don't ruin anything that you have done until this part works first.
Have the original sinsplus mod with all the original folder and files copy the gameinfo folder out of it to a different place. Now copy the gameinfo folder from v 1.11 into its place. Once you do this go back to the sinsplus gameinfo folder and select all the files and copy.
Now go into the gameinfo in the sinsplus with gameinfo v1.11 and paste, make sure not to overwrite any of the same exisiting files just do no until complete. this will write all the new files that are in the sinsplus gameinfo to the gameinfo v1.11 in our new sinplus mod directory. I know its a hassle and takes a bit to go through all the files this way, but its an easy way to get all of his files in there. Now once your done with that then you need to copy gasgiant.entity and GalaxyScenarioDef.galaxyScenarioDef files from sinsplus gameinfo to the sinsplus with the v1.11 gameinfo that is in your new sinsplus mod folder. Overwrite the existing files since the GalaxyScenarioDef.galaxyScenarioDef contains the new planets info for the game.
Copy it to your mod folder load the game run the mod and you should see all the planets.
let me know if this helps.