My suggestion... Since we have and still are dealing with this...
Don't make a big deal out of it. If he goes in his pants, while you're changing him tell him how yucky that must feel and you'll get him all cleaned up. Clean him up and tell him how much better he must feel and maybe next time he'll go in the potty. Do this all in a very calm manner. He'll eventually give up and go!!
This is what we did for my son and he just one day asked to go on the potty. Then again, some days he still goes in his Pull-Up at nap times. But I tend to think that's becuase he likes his privacy, something hard to find around here on a normal basis!!
Don't worry it sounds like both of you are doing GREAT! "They" do say that it takes at least 6 months to full train during the day and twice as long if not more for at night! Keep up the good work!!