Potty Training

I am going to need some potty training advice. We got Gambit late yesterday (pics to follow). He doesn't seem to want to potty outside. It's a brisk day and he is very tiny, and he trembles like a leaf when we are out. I wait about 10-15 minutes each time saying "go potty, baby" but he doesn't go. He DOES seem totally fine peeing and pooping in his crate, after which he barks to let us know he has done something and to please bath him now as he has stepped in it. So far he has had his little toes bathed about 4 times, and has pooped three times since coming home last night (a lot for such a little dude). The breeder encouraged us to get a bigger crate so he could sleep and eat in one end, and that we could put newspapers at the other end for him to go if he needs to. He seems totally comfortable just going in his house and then telling us he was a good boy and pottied in his house. :( I am waiting for his instinct of "don't pee in my own house" to kick in, but so far, he seems to feel that is the best course of action.

I will buy him a sweater so our trips outside aren't something to fear. But what do I do in the meantime? He ate and wouldn't go; It's been 15 minutes since we came back inside, I'm going to take him out again.