By the way, it is TRUE that amps times volts is watts in DC (steady state, not pulsed).
But again, the question was about volt-amp ratings. To further cement this, next time you are in Office Depot, or a computer supply store, check out the backup power supplies... their output is 110v ac, and the largest rating on the box will be volt-amps... examine the box carefully, you may find the wattage rating, and it's different (and usually less).
My best advice is do not buy a power supply that has a volt-amp rating ONLY.
Regards, Greg