Cisco WLC AP MTU Size

I also posted this on the Cisco sub.

We have an issue where UDP traffic is being dropped at one of our remote sites because the DF bit is set on the AP traffic but the size is larger than 1500 (after ipsec). I have found how to adjust mss size for TCP but I can't find anything for UDP. I also don't see anything for MTU at all. How can I either manually change the MTU on the AP interfaces or set it so that fragmentation is okay?

Thanks!