How to edit textures with texture paint in Cycles like GLSL in Blender internal? When I edit my textures (color, spec, normal etc.) in cycles I can only see the texture that I am currently editing. 

Sometimes when I edit one specific texture, e.g. when I edit the bumpmap, I want to see all the other textures to get the best result. 

In blender internal it is possible by using GLSL shading. Is there a way to do that in cycles as well? 

All textures are mixed with mix nodes. The last mix node is connected to a Shader Output node. Cycles renders everything correctly, therefore the node setup is okay. However, I cannot see all textures together in 3D View.

Can you help me?
You could try the viewport shading to Material, it will display image textures as mixed in the shader node setup:



From the wiki:


  Material: a simplified version of the entire material is drawn using
  GLSL shaders. This uses solid lighting, and also is mostly useful for
  editing, painting and mapping textures, but while seeing how they
  integrate with the material.