This paper focuses on the study of the superelastic behavior associated to the stress induced martensite transformation in a Cu-12.5%Al-0.5%Be [wt.%] shape memory alloy. Neutron diffraction was used to track the evolution of stress in the (beta(1)) austenitic phase during the onset of the stress-induced martensite phase change. A thin flat and a cylindrical specimen was analyzed, allowing us firstly to evaluate the stress evolution in the austenite phase during martensitic transformation with laboratory X-ray and neutron diffraction and secondly to compare differences between methods (sin(2)psi, principal stress) for in-situ neutron diffraction experiments.