  In this paper we introduce a new multiparametric technique that attempts to
tackle simultaneously the problems of composition determination and hadronic
interaction uncertainty. Employing simulations of a real world detector under
its planned operational conditions, and disregarding systematics, we can asses
that the present technique should be able to determine the composition of a
binary mixture of p and Fe with a statistical confidence of few percent, in a
way that is independent of the assumed hadronic interaction model. Moreover,
the combination of real data with the tools developed and presented here should
give an indication of the reliability of the various hadronic interaction
models in current use in the area. We center our study in the region of the
ankle, where composition carries critical astrophysical information, and use
two main parameters: the number of muons at 600 m from the shower axis and the
depth of the shower maximum obtained from the hybrid operation of the planned
muon counters and high elevation fluorescence telescopes of the AMIGA and HEAT
Auger enhancements.
