By chance, I also bought the NB-BlackSilentFan XM-2 from Amazon. Of course, ended up paying twice the price as it had to be shipped to Singapore. Also, not sure the differences between the XM-2 vs XM-1. Anyway, here's what I did. The plastic connector block has 3 small holes on side. Gently tug the wires, then with a sharp tool (paper clip or toothpick), press one by one, the 3 metal connectors thru these holes. It should allow you to pull loose the three wires, white, red, and black.
Now you can match the three wires order with the original fan, which is white, black, red, then insert the metal connectors back into the plastic block. Remove the original fan, replace it with the XM-2 fan, connect, and you should now have a very silent NAS box. It really is quite impressive the change in noise level.