How to paint with the clone option in Texture Paint? I would like to use the clone tool with texture paint, but as soon as I choose Texture Paint, the mesh is white, and I cannot paint on it. 

I created a new UV Map, after I project the image from view, the image of reference appears well on the mesh in Object Mode, but I get this white color in Texture Paint Mode. I followed this tutorial : https://youtu.be/p4ngVoGIj1Q?t=15m56s but the version of Blender is not the same, so the settings are a bit different.

I tried to play with the clone settings, the options in the shader menu : GLSL/Multitexture, but nothing changes.

Would you know how to use this clone effect in Blender 2.72b ?



EDIT #4: it is confusing, sorry. Here is a new example : the clone painting works. But when I click on the paintTo UV Map, which is the image I should export at the end, the painting does not correctly match the seams :

This is when I paint :



This is when I click on the uv map : it is not the same result as the previous painting :



Here are the files :

http://www.pasteall.org/blend/35661

http://www.pasteall.org/pic/86965
When the render is set to Cycles you can add two textures to the material and they should both show up as slots in texture paint.  Be sure to add a UV Map node for each texture and set the appropriate UV Map.

Enter Texture Paint mode and activate "Clone From Paint Slot".  

The texture that is being painted to should be selected in the section named "Available Paint Slots"

The texture that is being painted from should be selected in the section named "Source Clone Slot".

All the settings I used are shown in the following animation.



Update in response to a comment requesting more information.

Textures can be drag 'N dropped from the hard drive file system.  They can be added in as texture nodes by looking through the menu that is called up when the keyboard shortcut Shifts is used.  They can also be added by drag 'N dropping the image icon from the UV Image Editor.  



Using Blender Render you can add images to the texture slots.  I think the limit is 18 slots per material for BI.  I'm not sure if the BI node editor has the same limit, probably not.