  This paper presents the detection issues for the lightest slepton
\tilde{\tau}_1 at a future e^+e^- TeV collider given the dark matter
constraints set on the SUSY mass spectrum by the WMAP results. It intends to
illustrate the importance of an optimal detection of energetic electrons in the
very forward region for an efficient rejection of the
  \gamma\gamma background. The TESLA parameters have been used in the case of
head-on collisions and in the case of a 10, mrad half crossing angle.
