You might have a little resistance, if not more. Our pom was about 6 months old when we brought him home and he was pad trained as well. It took several weeks of training to get him to go outside.
Best thing I could say, and I'm definitely no pro, but just what worked for us, is to establish a routine. Walk the same paths, stop at the same spots everytime. Try to go on your walks as close to the same time everyday. Keep treats with you and reward her when she goes outside. Make a spectacle out of it.
Not sure if it was a placebo or not, but this spray worked for us. We took him to the same spot everyday, sprayed that on the base of a tree, then just stood and waited a while (like 10-15 minutes each time). Eventually he got to where he would go in that spot, and we would give him a treat and praise him every time. All the while we used a keyword, "potty." In our case when we put his harness on, latched the leash, and throughout the process...
Now, about 2 years later, when we asks if he needs to go potty, he'll perk up and start spinning in circles. It may take some time, but I'm convinced that with some consistency you'll get there. From what I've learned, poms LOVE routine.