There is definitely a waist belt on the 580 as well as some of their other blowers. Mine is a year old. It's listed in the features for the unit as well.
And yes, Husqvarna owns Redmax but not all their products are the same. Husqvarna has "borrowed" some of the Redmax units and modified them a bit. I don't know if Redmax has rebadged any Husky stuff though...don't think so.