Bump. I really wish Poweramp had this. Google Play Music has it and it works great. I don't really want to go through the trouble of setting up playlists. Plus, the great thing about Instant Mixes is that I don't know what tracks I will hear. Shuffling through playlists is not the same thing. Please add support for creating instant mixes!!
The post linked above only references live streaming. I don't think the OP was asking about that. I would also love to be able to use Poweramp with Endomondo. Unfortunately, Endomondo only seems to work with the stock android player, Google Play Music, or musixmatch.