The performance of systems employing bit-interleaved coded modulation (BICM) critically depends on the availability of soft information. In the multi-antenna case, the extraction of optimum bit-metrics becomes prohibitively complex, so that suboptimal solutions need to be adopted for practical implementation. Instead of considering all the spatially multiplexed streams jointly, the implementation presented in this paper computes the soft information on each data stream separately, based on the output of an MMSE equalizer.