No, it's not a licensing issue, it's a hardware issue. Tao does not have their software able to run on hardware that PalmOS compatibles use. And unless Tao makes it happen, Amiga cannot run on PalmOS devices. It has been rumored for some time now that Palm is looking to upgrade their CPU of choice, and with it the PalmOS. The new CPU would be one that happens to be compatible with Tao's software, which would then make it compatible with AA/DE.
Don't forget that Amiga does not choose where the DE/AA technology runs. They rebrand Tao's technology. They've yet to add any further logic on top of Tao's product. So, if Tao gets their stuff to run on PalmOS, then Amiga gets to run DE/AA on PalmOS.