I don't know anything about this other than the fact that there are many people reading these cooking sites looking for a job as entree into the States. I've been e-mailed several times from people seeking help in entering the states thru culinary employement.
I tend to think you should advertise on the web at some of the professional chef sites....but I have know idea what the quality of the respondants might be. There are areas at these sites that let job seekers post what their looking for so you could find a match with-out posting your own ad.
Here's acouple to check out: www.starchefs.com,
society of mad chefs.com
There are several companies that head hunt in this industry. You have to pay for the service but it could provide you with links to professionals that will fit into your establishment. You'll find one or two at starchefs, that have posted lists of positions their looking to fill.