Shannon,
 
I had the same problem with Meeko going on the second level of her condo.
(The goofball would go exactly where the litter box was...but one level up!)
I tried cleaning, telling her no and putting her in the right place, but
nothing worked.  I finally gave up and bought a triangular corner pan.  It's
plastic and has two hooks for the back of the cage put they didn't secure it
well so I took an old shoe lace and tied it to one hook and looped it around
the bars before tying the end to the other hook.  We had one or two
incidents of Percy (male, 4 mos., plays with anything) getting in and
throwing all the litter down the ramp but he grew out of it soon.  He tries
things a few times and if they don't get the reaction he's looking for he
moves on.
 
I've had it there now for about two months and they both use it (when
they're too lazy to go down to the big box).
 
Melissa (Human Mama)
Meeko (Spoiled Princess)
Percy (The Great Adventurer)
Merlin (Poor Dog, aka Chew Toy, aka Launching Pad)
[Posted in FML issue 1565]