Sony Ericsson Xperia Arc — Headphones problem

Hi.
I am wanted to use original headphones that came in the boks with my XPERIA ARC. But when i plug it in i get mesage (Headset not suported). And same hapens on other ARC i have, but if i plug it in LG it works fine, and if i use headset without MIC it works fine. Så what is wrong?.