Can anyone tell me how to search for government fare availability on flights?

I am required to book through our travel agency and so I usually check seatcounter.com before calling them so that I know which flights have availability in which fare classes. But I don't know how to tell specifically which fare class the government fare comes from. I've always been succesful in the past when I saw availability in Y and the next 2 or 3 classes below it, but this week I tried to book a DL flight SNA-PHL that had seats available in all but the lower 4 classes (T,U,L & K) and the travel agent informed me that for this route the Gov fare is in K class. So I learned that apparently the Gov fare comes from different classes for different routes?

So all that said, does anyone know how to find out what fare class a Gov fare is in for a specific city pair?

As I understand it, the government fares are often a sub-bucket inside the various fare classes, so you may have some government fares in "Y", some in "W" and some in "V". The contracted travel agency (Carlson Wagonlit, SATO, whatever) can see what government fares are left at any time, so you may see "Y9" showing even though there are no more "Y-government" seats available in that bucket. At least that's the way it seems to work on international flights; I've found availability in a class but the travel agent will say there are no government seats left in that class.

Government fares are always available on the airline that has the City Pair contract for a given route and you are eligible for a government fare. Keep in mind that they are basically discounted Y fares and not always the best fare on every routing.

Here is a tool to view the fares for FY2008;

http://apps.fas.gsa.gov/citypairs/search/

If you are flying on the contract carrier (which is required in most cases), there is ALWAYS availability - that's part of the government contract, which is even if there is only 1 seat available in Y, it must be available for government travelers. For some government contracts, there are seats available only in Y. For other government contracts, there is both a Y class and a discounted government fare, for which the fare class letter varies by airline. When the discounted fare class is sold out, you are still able to book in Y class. I've been a regular government traveler for 31 years, so I am speaking from experience.