Just checking the ep in question:
You see five jump points open.
However, I believe this:
The White Stars were surrounded by the Omega-Xs as they jumped in around them, and there's definatly

of them as Ivanova says they were outnumbered (she may have been also talking about Thunderbolts, but fighters usually don't threaten a White Star so I assume she means Omega-X classes'
I counted at least twenty one whitestars by doing frame by frame.
And I think in B5Wars it states that there were 30 Omega-X at the battle, there is something that does (maybe it was JMS himself?)
There was a number for them somewhere.
What I would do is have Omega-Xs just be brought into the battle at a certain time, along with White Stars to give the illusion of a lot of ships (of course, they would enter with no jump vortex).