Using spin-resolved SANS (POLARIS), we will investigate the magnetization-reversal process of Co and Ni nanowire arrays. Since the magnetization reversal is largely determined by transversal spin components, we aim at extracting the ensuing spin-misalignment SANS cross section through measurement of the spin-flip cross section. The proposed spin-resolved SANS experiments will provide insights into the size of the characteristic length scales during magnetization reversal. More specifically, we expect to answer the questions whether the reversal takes place "wire by wire" or in a more cooperative fashion and what is the size of the magnetically perturbed region relative to the structural size of the wires (length, diameter).