I've only communicated with DoMore plc's from Aut. Dir.
Their DL05 manual leaves a lot to be desired from a quick glance.
I'm surprised you can map directly to an output. I would have expected an internal register only.
Anyways, I'm no help but I'd post this on Automation Direct's forum. Or you can call their tech support. Their support is very good and unlike AB, it's free.