Adding a planet type

Ok, I am sure it is something relatively easy... but I don't suceed to do it...

Here my problem... I try to add the planets of the mod Sins_Plus__by_Uzii__v1-3a because I only want the planets and nothing more

I succeeded to add the textures, to remove the bonus etc... I can even see one of them in the game (cause I modified the file PlanetTerranHome.entity to look like an urban planet).

But all the news planet refuse to show...

I also modified the file GalaxyScenarioDef.galaxyScenarioDef so it is not really the problem...

The problem is about the new entities that are not defined, and I can't find where we can say to the game that one planet is that etc... (exemple: That an urban planet defined in GalaxyScenarioDef.galaxyScenarioDef as "orbitBodyType "City"" can be found in the file "PlanetCity.entity").

The debug file confirms me that by reporting me:

GalaxyScenario type name is not valid. The EntityDefName is not available. TypeName:'WeightedRandom' -> EntityDefName:''.
GalaxyScenario type name is not valid. The EntityDefName is not available. TypeName:'WeightedRandom' -> EntityDefName:''.

etc...

So, who can tell me the file I have to modify?

Sidenote: all mod tools refuse to work on my computer... Galaxyforge doesn't load, Developer Exe warn me about a lot of errors etc...

But I have looked to the documents in it... and it is not explained in them

So I use the notepad... and afterall I prefer that...