I am in the process of potty training my daughter, who will be three in December. Like your daughter, she was very reluctant to sit on the potty and would poop in her underwear minutes after I sat her on the potty. I say we are in the process because she still doesn't go #2 regularly and we still have to reward each time she uses the potty, but we've not had a #1 accident in about a week.
A friend of mine told me how she potty trained her eldest daughter and I immediately knew it would work for my kid.
I went to Target and I bought a fancy birthday hat and a birthday candle that sings Happy Birthday. She was with me when I purchased these items and I made a bid deal over her only being allowed to wear the hat while she sat on the potty. Despite her crying for me to let her put it on her right then, I said NO. When we got home she immediately went to sit on her little potty. Then I gave her a nice big glass of water and a salty snack. I put little bowels of salty snacks throughout the family room and encouraged her to eat and drink as much as possible. I also put on a new DVD for her to watch and put her potty in front of the TV. Every 10-15 minutes I would ask her if she wanted to sit on the potty with her hat. It took about 90 minutes, but she finally peed in the potty. Of course, I made a HUGE deal over it and after washing our hands, etc. We lit the birthday candle and sang Happy Birthday to her. She also got a temporary tattoo on her arm so she could show Daddy when he got home. Then I repeated this all day long. We did not leave the house to run errands, etc. By the next day I was able to relax and she would tell me when she wanted to sit on the potty, but I would try to have her sit first thing in the morning, 20 minutes after eating, and before her bath. It took two weeks before she would go #2 in the potty. It was a lot of laundry because I used training pants, not Pull-ups.
Some suggestions I have for you are 1) get a little potty that she can sit comfortably in. I actually keep one in my van for long road trips. 2) Don't use Pull-ups, get training pants and 3) plan a day when you and Daddy are home all day to really focus on potty training her.
A note on the tattoos: I heard another daycare provider did this, one tattoo each time the child went. Well, it really is ugly having tattoos up my daughters arms. They are also not that easy to remove because she complains when I scrub them. But, she really likes showing Daddy how many times she used the potty that day, its a physical reminder that doesn't disappear like a sticker or candy (my kids pull stickers off a sticker chart). It really works and because I also have a husband that works very hard, he enjoys counting the tattoos with her each morning.
Wow! I really wrote a book this time. Sorry about that.
Good luck!
N.