DM8 Eye pipes can be replaced with the DM9 item and detent system, these are available to purchase from any Dye/Proto dealer IIRC (I'm sure Tommy or Ash will correct me if not).
Thanks for the help Silver but I was after it for a pm8 not a dm. I'm going to try Just paintball tomorrow as they seem to be the only company I can find that stock them over here. I am probably incorrect though.