Make readable Heightmap Texture Dynamically Generated

Hello everyone,

First i apologize for my bad english :p

I will try to be clearest as possible, I need to passed "Readable" Heihtmap png dynamically generated.

--> Context : I work on TD project since couple of month, I included a Level_Editor scene. With this one, i can modify terrain Height and texture, and place path, finish and startpoint. When i saved the Map, i analyse the terrain and create the Heightmap.

Problem, when i try to import the Heightmap on terrain in new scene, ERROR need to passed this texture to Readable on ImportSetting. But i'm on runtime, not Editor...

The project is really close to end(alpha ofc), and i'm stuck with this since 2 day, please help me :p