see here - http://tf2maps.net/showthread.php?t=16 its already been doneis it possible to decompile a map to use as a reference?
see here - http://tf2maps.net/showthread.php?t=16 its already been done
Remember kids, reusing bits of Valve's maps (or maps made by anyone else) is wrong and posibly illiegal (not entirely sure about various laws)
So never copy something straight from it. Look at it by all means, study it, live by it, use it as a bible(or loo roll if you take offence at the idea of using it as a bible) but don't copy and paste it!