I had this challenge with DD1. She'd go if we asked but never initiated on her own. We had to go commando for a day (but no accidents to clean up!) to get her to initiate it. Not sure why that worked but it did. To me, taking her to the potty every 20min or 1hr or whatever wasn't really potty training per se. Sure, she'd go potty and we'd avoid an accident, but it wasn't her becoming independent with it.
Mom to two amazing DDs ('07 & '09) and a fur baby.
Gluten free since Nov '11 after non-celiac gluten sensitive diagnosis. Have had great improvement or total elimination of: migraines, bloating/distention, heartburn, cystic acne, canker sores, bleeding gums, eczema on elbows, dry skin and scalp, muscle cramps, PMS, hair loss, heart palpitations, fatigue. I'm amazed.