Make VrayLight not contribute to alpha?

I have a VrayLight set to dome that has a HDRI texture mapped to it. I want this to render in the scene, but would like to make the sky as an alpha. Is there a quick setting for having the VrayLight not contribute to the alpha, but make it visible to the scene?

searchy, searchy… http://www.chaosgroup.com/forums/vbulletin/showthread.php?t=40948&highlight=dome+alpha (check out the end of the thread)

nice solution. thanks.