OK. I've been looking at power steering fluid in the stores, and most don't list what specs they meet. Those that do, list a different Ford spec than M2C33.
I'll have a gander at the ATF fluid bottles, and also look at my manual again for more details.
One more question, though: If I'm just topping off my system, is there a combination of fluids that might cause harm? That is, if the system contains M2C33 (whatever that is) and I add any old type F ATF, am I going to be OK?