HELP! Potty training a strong-willed toddler!

I have tried to start potty training today with my 33 month old daughter. I thought she was ready as she has started to tell me when she is weeing and is tugging at her nappy when it is soiled. So far she is refusing to sit on the adapted toilet seat (the kind with the steps and small seat) She is interested in the travel carry potty (which looks like a penguin) but I have only been able to get her to sit on that one for more than 30 seconds by giving her treats and there have definitely been no wees there. Since we got up we have been encouraging her to wee on the potty. We have her in a dress with no nappy so she can see when she has an accident. She has done 9 wees in 5 hours but none on the potty. We haven't told her off of course and she is starting to help to clear the mess up. I am making a big fuss when she sits on the potty and giving her a treat, even if only briefly, but how am I supposed to reward her for weeing on the potty if she won't even sit on it long enough? Do you think she isn't ready? Do I try putting a nappy back on her and then try taking her to the potty on a regular basis to see if I can get her to go on the toilet or do I just carry on with this? All I feel I am doing is training her to wee on the floor at the moment!