You can book the free dining promotion right on the WDW website now under special offers. Do you see the promotion listed on the Travelocity website to book?
I don't think so, in order to get the free dining you have to buy at least a 1 day myw park pass for yourself and every one in the room. The prices I checked on travelocity only included flight and room, no park passes and in order to get the free dining you have to pay rack rates and I believe travelocity's rooms are discounted. I could be wrong so hopefully you'll get another answer from a more knowledgable dis'er but I think that's how it works.
I believe that last year they did offer rooms with free dining and tickets but you had to select this package; it was a special offer. Expedia does not really discount rooms beyond what disney does in my experience (maybe some one can confirm) and they might not have these packages this year as many rooms w/ FD are already sold out. I think you would be better off trying to book for your dates online through the link on the Disney site and then getting a room refund from travelocity. The 25 dollar penalty will be worth the free dining. I did this last year (but just to get dining as you cant get this through travelocity and disney cant touch your ressie if its not booked through them) then free dining came out and I was able to get that too
You have to specifically book a Free Dining package. It's not something that gets automatically added on if you purchase room and tickets during that time period. It would be probably best if you book through Disney or AAA and ask for the Free dining package.