  Various differences in galaxy cluster properties derived from X-ray and weak
lensing observations have been highlighted in the literature. One such
difference is the observation of mass concentrations in lensing maps which have
no X-ray counterparts (e.g. Jee, White, Ford et al. 2005). We investigate this
issue by identifying substructures in maps of projected total mass (analogous
to weak lensing mass reconstructions) and maps of projected X-ray surface
brightness for three simulated clusters. We then compare the 2D mass
substructures with both 3D subhalo data and the 2D X-ray substructures. Here we
present preliminary results from the first comparison, where we have assessed
the impact of projecting the data on subhalo identification.
