Thanks! I just tried IMExchange 2. It is a free download with a free trial period, then in-app unlock to get the full version for... I'm forgetting. $8? Getting it set up was a pain. For some reason the username entry keyboard did not have a backslash character, which I needed. I had to type that into Notes and then copy it into the field in this app. Weird. In any case it seems to be working. TaskTask is cheaper, but there's no free trial. Hmm.