MJung -
You are correct. Hydraflow can not accept a double out pipe. Nearly 100% of the problem is FLOW DIRECTION and the doubling of outflow.
I presented a quick 1 hour webcast a couple of weeks ago at www.civil3d.com. I think the guys at EE have links to the recorded webast.
By the way - there are a couple of items that I am currently working on for my AU paper to help make this easier - cause deleting in redrawing is a pain. Amazingly - its already built into the program - just I can't seem to find anyone else who is talking about in the way I am doing it.
Matthew Anderson, PE
Matthew Anderson, PE CFM
Product Manager
Autodesk (Innovyze)