In case people don't see it, here's a reply I posted down in the screenie forum.

You can just copy over your FS9 AI traffic bgl file into FSX and it'll work. I suggest that you first take a backup copy of the default FSX aircraft folder as there are so few aircraft in it and then copy all of your FS9 AI aircraft into FSX.

There you go - AI traffic.

You can for the time being also create/amend your FSX AI traffic by doing it in FS9 using TTools and then just copying the BGL file over .