Potty Training

My Ezra. He is 3.5 years old and that boy does not want to be potty trained. Aidan was easy. He had no big accidents and was thrilled to use the potty like a 'big boy'. My boys have proven to be different in every sense of the way!
We've been working on training, very loosely, for about a month. Ezra has gotten the idea and knows how to use the potty. But it always has to be his idea. Today, by 10:30 a.m., he had tried to pee in the potty and somehow UTTERLY missed and then peed his pants later in the morning. I am feeling pretty darn frustrated. He needs to be fully trained by the beginning of school this September and I am starting to get nervous. We have done the sticker charts, the potty seats... But at this point I've done all I can do and it's up to him. The only think left for me to do is clean up the pee.