If you are using rw weather, FSC is able to show this data when you enable the weather downloads. Since FSX does the same, the chances are high that both programs match on their data input.

Now the problem arises if there's a different data set or if you have more options on the runways in use. This could be a parallel runway situation or one where every available one will have the same amount of crosswind. You can't really predict the FSX ATC decision, unfortunately.

With an external weather program, there often is a flight plan option to import plans and catch a glimpse on the weather data before running FSX itself. However, when using FSX ATC, the same situation may arise. No precise prediction possible.
You could use online ATC or some addon software to counteract this. I think RC4, PFE or VoxATC are more predictable and/or able to offer some more takeoff options.
Perhaps the hard way in FSX would be to just take off on the runway you prefer and later enable the ATC or something. I haven't tried, but that's what I would do if the program is to rigid on choosing the right runway.

If you have special airports where they take off with a certain amount of tailwind and only switch if this amount reaches a certain limit, the default ATC won't be able to cope with that. The rw operations sometimes run that way to keep the noise abatement routes intact unless the safety is severely affected with heavy planes taking off/landing in tailwind situations for example.
So you may see some major hubs working in the wrong direction until e. g. 5 kts of tailwind on the active is exceeded over an amount of time. The actual limits depend on the airport of course and the planes taking off or landing also have some manufacturer and/or airline limits they operate within.

Nice video on a 'too much tailwind decision'. Bad ATC guy, telling wrong values. http://www.youtube.com/watch?v=36g83GkG1eU