Almost 3 y.o. boy won't poop in the potty - Go back to pull-ups?

Sigh... Around Christmas time, we made the switch to big boy underwear and only used pull-ups at nap time and overnight. Now he stays dry all day and night when it comes to pee. He's got that down. So he wears underwear all day long. But my son will poop in his pants every day. At first I wanted to keep at it with the underwear. I was using my fair share of OxyClean soaks and it was fine. But here we are months later and it's still happening daily, usually while he's at daycare (which means they aren't as quick to get the underwear off of him and I come home every day with a bag of dirty underwear that's a lot harder to clean after sitting like that all day). I'm wondering if I should just keep him in pull-ups during the school day to save my laundry efforts. But I hate to go back to pull-ups all day just for his #2s when otherwise, he's doing great with the potty.

What is your opinion -- keep your kid in pull-ups until they're 100% potty trained (including #2s)? Or just keep on the with the underwear and one day we'll get there? BTW -- I'm doing all the usual tactics for trying to get him to poop in the potty... asking him, sitting him on the potty at his "usual" times, incentives, having him watch when we empty from the underwear to the potty, blah blah. He's not interested. My worry with the pull-ups is that it's like reinforcing that it's okay to go in his pants. Not sure how to proceed. Thanks!