How to Put Composite Fog Inside Sapphire Spotlight

Hey guys, I am trying to composite smoke footage inside  Sapphires S_Spotlight Plug in. From the frame you can see its inside the spotlight however the outside of the spotlight its still visible. I have fiddled with masking settings and they all seemed to do something other than totally remove the areas, I'm pretty sure I done something wrong. I also used CC composite which did reduce the opacity to the areas outside the spotlight - I just want the sole beam and fog to make the light more interesting. I am sure it is simple, any thoughts ?