All current Intel based sockets have backplates. Do not remove the backplates as this is to hold the retention module in place. Stock Intel fan won't interfere with the backplate, it uses a push pin mechanism. If you can't install it, then you're probably not installing it correctly.
Just out of curiosity, what CPU did you get?
On newegg there are only two evga p55 mobos and it didn't look like the backplate interfered on either of them. However, I recently bought an i5-2500K and I had a heck of a time installing the stock fan until I figured out how it worked. This is what my fan looked like:
There are little black pegs that push down through the white feet and spread them out so that the feet are secured behind the motherboard. If you push down on the top of the peg and the black part goes through the white feet before the feet go through the motherboard holes then the harder you push, the less likely they are to go in - that's what happened to me. I pulled up on the black pegs until they came out of the white feet and then pushed gently until the white parts were through the mobo holes. Then I pushed harder and the black pegs went through like they're supposed to. This might not be what happened to you, but that was my experience with the stock cooler.
One thing I do know is that you should not take the backplate off the mobo. You will void your warranty and break the board.
Because of the backplate on my motherboard, EVGA p55 FTW. Does this mean I have to buy a real cooler or can I take off the bracket somehow.
The cooler goes on top of the cpu chip, not on the backplate.
DO NOT REMOVE the backplate.
To mount the Intel stock cooler properly, place the motherboard on top of the foam or cardboard backing that was packed with it.
The stock cooler will come with paste pre applied, it looks like three grey strips.
The 4 push pins should come in the proper position for installation, that is with the pins rotated in the direction of the arrow,(counter clockwise) as far as they can go.
Place the cooler so that all 4 pins are oriented over the holes in the motherboard.
The trick to getting it on is to push down on a diagonal pair of pins at the same time. Then the other pair.
If you do them one at a time, you will not get the cooler on straight.
Lastly, look at the back of the motherboard to verify that all 4 pins are equally through the motherboard, and that the cooler is on firmly.
This last step must be done, which is why the motherboard must be out of the case to do the job.
It is possible to mount the cooler with the motherboard mounted in the case, but you can then never be certain that the push pins are inserted properly.
If you should need to remove the cooler, turn the pins clockwise to unlock them. You will need to clean off the old paste and reapply new if you ever take the cooler off.