For Andreev spectroscopy to be a useful tool to detect spin accumulation in semiconductors, we show by simulation that there is a maximum value for the interface scattering parameter that can be tolerated. Three different fabrication routes for Pb/InAs planar junctions are explored and we find that the "etch-back" processing strategy is the most promising. Using the parameters extracted from the spectroscopic analysis, we find that the interface properties fall into four different regimes of behavior. (C) 2008 American Institute of Physics.