Piston

Hello!! I bought a Toyota Altezza with the same squeaking noise, it cames from the hole in the bodywork where the seatbealt comes from, it sounds when I accelerate and when I brake, it seems that is from the bodywork or inside of that iron pole, maybe a screw or I dont know, the worse I think is that It cant be lcated cause is an iron part... :S... Im gonna take a video with the sound later