Nimbus,
though OPS staff is usually listed on the release, they do not excercise operational control over the flight, the commander is.
Also, European carriers do not need a FAA dispatcher to sign off their release, when they operate in the U.S.. This procedure wouldn't make sense, since the FAA cannot force the FARs onto foreign carriers (demanding from U.S. carriers to drop their shared responsibility would be just alike).
Re hiring, well this is a sore point. A FAA license is definately a plus, though some of the bigger airlines (DLH, SWR, etc..), still might require a license that was/is applicable under national law (i.e. their staff is still trained to standard). Under JAA the Flight Ops Officer does need adequate training (as defined by the individual Quality and Training Manuals). Guess the prime issue to do that is/was money (dispatchers without a license don't have to be paid just as good as licensed staff). So, let's continue to keep the best kept secret of the aviation industry a secret, until, well I'll leave that point up to your imagination.....
Cheers
fcit