The Phantom has 6 wholes on the top between the 200mm(190-192mm fans actual).
It should look like this
o o o
o o o
what you want is the four on the right side.
You would also need to go to Home Depot and buy some 1 1/2 Screws that look identical to the ones that come with the Corsair H100, but a little longer. It should go for about $2.19 [Tax Included]
Issues you might get into is if your ram has heatsink spreaders, you would have to break the top 2-3 to get it to fit, but if you have low performance ones like A-Data or Mushkin then you're good to go for adding the 120mm fans that comes with radiator.
But of course, this will stop you from buying ram coolers because they can no longer clip into the ends of the ram slots because the top would be blocked by the 120mm fan. I bought a Corsair Dominator GT Fan, and will try to mod it and let you know.
If you do decide to buy a RAM cooler, the Antec Spot Cooler should work fine.