  We explore a relation between four-dimensional N=2 heterotic vacua induced by
Mirror Symmetry via Heterotic/Type II duality. It allows us to compute the
\alpha' corrections to the hypermultiplet moduli space of heterotic
compactifications on K3xT^2 in the limit of large base of the elliptic K3. We
concentrate on the case of point-like instantons on orbifold singularities
leading to low-dimensional hypermultiplet moduli spaces.
