Here is what I had to do to get it to work with our custom menu:
Create a cfg file named Load_InRoads_SS2.cfg with Load_InRoads_SS2=1 as the only line within it.
Place or create this file in the C:\cad\Bentley\MicroStation\config\system folder.
This will allow you to use the key-in, mdl load civustat.ma, as usual.
However, with the new inroads, 08.11.09.493 - SS3, I found that it does not call up the same way. I have changed our custom menu to call inroadsactivate inroads suite and found this also works for the SS2 version.
The BUT here is that I have not tried too hard to try and have both versions installed at once and what it would take to call them separately. If I use the same command I believe it calls the last version that was loaded from the menu.