Orieni space is/was off the lower right edge of the map, past Minbari space.
The map you're wanting (though some systems have moved a bit with Mongoose's interpretation of the system map) is contained in the Wars of the Centauri Republic Supplement for B5 Wars.
It isn't available to download online anywhere near http://www.richbax.com/
Though no sign of Fallav IV, but then that map is 800 years on from the events that led to the Technomages being set up. It could be that isn't now/never has been on the jump route network. This could be due to a variety of reasons (put your Evil GM thinking hat on for this...) Note that Earth isn't present on the network either at that point.
But that supplement will give you a lot of the history of the area.