First, I want to thank kingtd and PalChgo for writing and modifying this plugin.
Thought I give something back...through some trial and error, I was able to use the 'Send Manual Command' action to send commands to devices connected to my ISY99i.
For 'Control' - Input the different device commands. DOF, DON, DFOF, DFON, DIM, BRT
For 'Action' - Leave it blank
For 'Flag' - Leave it blank
For Node: - Input the device code. Ie. '18 CE 54 1'
I have no idea what the Action and Flag fields are used for. Maybe an UDI developer can chime in.