A method includes providing, around an end section of the pressure sheath, of a crimping ring that is intended to be introduced into the pressure sheath; placing, around the end section and the crimping ring, of an end vault of the end piece, the end vault having an engagement surface for engaging with the crimping ring capable of pushing the crimping ring radially into the pressure sheath; relatively moving of the crimping ring in relation to the engagement surface in order to crimp the crimping ring in the pressure sheath. The method includes, prior to the relative movement, a heating of the end section of the pressure sheath, capable of reducing the Young's modulus of the polymer material of the end section of the pressure sheath and of maintaining a reduced Young's modulus during the relative movement step.