How would you pronounce Osseo?

Well, with approximately half an hour sitting at the DQ/BP while
changing diapers, feeding Molly (for the second time in 2 hours),
going potty and dolling out pudding as a peace offering, we had plenty
of time to debate the issue. In the end, it took a phone call from one
of the locals to settle it.
It's AH-see-OH, for those of you playing along at home.