I am in US and my Wife is on H4 entering a class for MS in fall 2007. My question is after completing her MS , Can she apply and get OPT while on H4 Or She has to be on F1 to apply for OPT.

I am in US and my Wife is on H4 entering a class for MS in fall 2007. My question is after completing her MS , Can she apply and get OPT while on H4 Or She has to be on F1 to apply for OPT.?
I believe she has to be on F1 to apply for OPT or CPT... because H4 is a non-work visa , so no authorization to work on that status could be granted.. I'm in same boat!