Render to cubemap not displaying skydome?

Hi any help will be much appriciated, I am using "Render to cubemap" for realtime reflections on building windows in my scene. It works as far as reflecting surrounding building however it is not reflexting my skydome. Any ideas on how to solve this problem?

Thanks, James.

Link for render to cube map: http://docs.unity3d.com/Documentation/ScriptReference/Camera.RenderToCubemap.html