The extended features are enabled by the serial number you enter, or the active subscription information.
I have entered my serial number and I still do not have access to the features. I have just checked My Adobe and it says my serial is for 'Extended Photoshop'
Also, upon loading the splash screen does say CS6 Extended, but I do not have access to any of the 3D features.
Hey Chris, I managed to get it working.
Weird issue though, it asked me to enable OpenGL to access the file. When I checked under preferences, it was already activated. I turned it on and off and it worked.
So you had the extended version, you just couldn't use the 3D features without enabled the GPU.