I'd do everything that Sealtm2 has listed, but perhaps one other thing. Depending on what you want to do with your skydome you might want to run its diffuse texture out of the Ambiant channel at value 1(and set Diffuse to 0) in the material room. If it is mapped as a sky then it will self -illuminate and you won't need to worry about actually trying to light it. You may, of course, be doing something else with your dome and want to light it (like the inside of an arena or something).

 

PoserPro2014(Sr4), Win7 x64, display units set to inches.

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