Custom Exit problem

[blahblahbal]

I'm having a problem with a custom exit for MH. I set everything exactly how it is in the Mystic Realm, and set the front sector of the linedef that has linedef action 2:Custom Exit to 21(the level I want it to go to), but it keeps sending me to level 8 instead of level 21.

Also, is there a way to have a custom exit after a boss fight where the boss has "Object Special" on it?

 

[blahblahbal]

Okay, so I solved the going to map 8 thing, but there's still the issue of the second part. Anyone?