A theoretical and experimental investigation of the SANS structure factor of labeled triblock HDH copolymer chains, randomly cross-linked into a network, is presented. We combine the RPA method for the consideration of the strong interchain correlations and the tube model with a harmonic deformation dependent constraining potential, modeling the action of cross-links and entanglements. With this approach a successful description of the scattering behavior under strain is achieved. The sensitivity of the method allows the detection of chain splittings during cross-linking with peroxides.