AFAIR screws are located at bottom, they may be or Torx type or special 2 pin safety screws - there are special safety bits sets available for this
http://www.wolfcraft.com/en/products...s/p/index.html or similar.
As power supply is filled with epoxy resin then a recommend using rubber hammer to release epoxy from plastic case, sometimes thin blade must be used to separate epoxy from plastic walls.