Hadronic calibration of the ATLAS liquid argon end-cap calorimeter in the pseudorapidity region <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si61.gif" overflow="scroll"><mml:mn>1.6</mml:mn><mml:mo>&lt;</mml:mo><mml:mo>|</mml:mo><mml:mi>η</mml:mi><mml:mo>|</mml:mo><mml:mo>&lt;</mml:mo><mml:mn>1.8</mml:mn></mml:math> in beam tests