Add pause menu options?

[Arightwizard]

Hi, I'd like to know if it is possible to add a pause menu option within a map. (So whoever downloads the map will see it when they hit Esc)
Something like Coldsnap's Time of Day feature. (Not the function, just the fact that it has an option in the pause menu.)
Thanks,
-Arightwizard

PS: If I may throw in another question here, what I'd like to do with the pause menu is switch BSPs...(To change ground texture), if you could tell me how to do that as well, then I would seriously owe you. Thanks.