Well, not only EP630, but every tom dick and harry 3.5mm headphone will work with p990i... only thing is, u'll have to buy the HPM70 handsfree set, remove the earphones tht comes with it and attach the ep630 to the adapter in it..
U can even go for the el cheapo 50 bucks adapter tht comes for the fast port of SE phones, but i'll not recommend it..:no: Spend just a li'l bit more n get the hpm70 for 250 bucks..
The handsfree tht comes bundled with the p990i doesnt have an adapter...that is, the earphones are not detachable...so its useless...buy the hpm70..n u r free to use it with any 3.5mm earphone u want..