We study the process of light scattering by optical solitons in a planar waveguide with an inhomogeneous refractive index core. A modulation of the core refractive index can be achieved by well-established techniques for producing waveguide arrays, e.g. by etching the surface of the waveguide cladding. We propose the special triple well configuration of the core, which supports resonant transmission as well as resonant reflection (Fano resonances) of light by the soliton, the latter resonance effect being a fascinating and unique property of time-periodic scattering potentials in one-dimensional systems