I can't found an object to recolored him...

Thank you so much for your answer...
Yeah it's really sad... But...
When i read this "not been added to studio yet", i hope this coming soon ^^.

yagwit Studio still can’t clone some items from build mode. But you can use workarounds.

I created ladders, columns, and spandrels using S4S. I also managed to clone a wall trim that is similar in structure to a frieze. So you can try creating it in S4S, I think.

There are three ways of cloning and extracting meshes and textures from a build item. The first two involve TSR Workshop.

1. Clone a frieze from TSR Workshop and extract the textures as PNG or DDS and the mesh as WSO. You will need a Blender plugin to import a WSO.

Syboulette says here:

NOTE: You’ll need to install the TSRW plugin to import .wso files into Blender. Go into the installation file of TSRW (C:\Program Files (x86)\The Sims Resource\TSR Workshop\Extras\Blender 2.74) copy the blender plugin (io_wso_import.py – the export doesn’t work), then paste into blender plugin file (C:\Program Files\Blender Foundation\Blender\2.76\scripts\addons)

This plugin doesn't preserve vertex paint when exporting from TSRW, however.

2. Clone a build item from TSR Workshop and export the whole thing as a package file (Edit > Project Contents > Export > To .package). Then, you can open the package file with Studio, go to the warehouse, select the mesh and click "batch export." Make sure you click BATCH EXPORT and not export. Export the mesh as a binary file and DO NOT CHANGE ITS NAME. Follow this video from about the 0:45 mark.



3. Follow the video instructions above from start to finish and grab the files you need from Studio's game file cruiser.

As for importing edited meshes and textures, and making a final package file, look through Syboulette's tutorials here and here and Qolygonal's tutorial here. Depending on what you're trying to make, not everything will apply to your project but these links provide good information, regardless. 

Edit: I should clarify. You can use TSR Workshop solely but TSR Workshop only works with .wso and .obj files. Not .blend files. You can use TSR Workshop to make a starting package file and finish it with Studio but extra steps are needed. I'm not aware of any way to clone a build item with Studio, but you can use it to extract resources from the game's core files with the game file cruiser. 

Thank you both so much for replying Fwecka (Lolabellesims) and qolygonal ! You both are truly kind.