Just a quickie...
I just found a very nice utility that would have helped a lot to confirm the right way to 'compose' D-STAR routings when I was first finding my way around (Icom manuals are no good for this, as I mentioned before!).
The WA4YIH "D-STAR Calculator", despite its odd name (IMHO), is a very nice little utility for demonstrating the various routings and commands that can be used in D-STAR currently (with the Gateway 2.x software and common extensions).
Though I've been au fait with the basic routings to ports/modules and individuals for a while (at least to initiate), this utility also shows how to do things such as linking and unlinking a repeater module to other repeater modules on the network - which I had only just been reading about, and have never tried.
Anyway, a very nice little tool that also hints at good practice with regard to announcing intention and calling CQ across bands/repeaters. If you're new to D-STAR and haven't played with this to get practised in setting up various calls, then I'd recommend it. Also, bear in mind that you should always put the gateway module in the RPT2 field if possible in order to allow dongle users to hear you. The "Local repeater with Gateway" and "Source Route" functions set out to do this.