With "psionics different," my first impulse would be to say that you're going to have retool quite a few of the encounters. None of the encounters are set up with psionic characters in mind; they're all meant to challenge parties wielding magic. I'd make sure you had at least one encounter per session where psionics, not magic, is a factor, otherwise you run the risk, at the very least, of your characters having abilities they never get to use (draining power points, for example). Trillith especially should pack some serious psionic punch, as Ryan alludes to above.
If psionics are the same as magic, your task becomes a little bit easier, but I'd still toss in a genuinely psionic opponent here and there just to make sure the psion stays interested and involved.
Good luck!