i say wait. Maybe encourage them to sit on the potty with dipes/clothes on and read books, have fun time in the bathroom? My sister hated the potty and waited until we went on a camping trip and rented a giant RV - the potty there was fun. So she learned in a weekend...
my dd on the other hand is at the other extreme. hates diapers, doesn't totally recognize when she's wet/poopy and yet every darn time mom's in the bathroom she's like "potty, potty, potty" taking off her dipes and pants.
On a positive note, she did poop once in the potty while i was on the phone in the other room. and she ran out, clapping for herself and smiling.