  Generalized Donaldson-Thomas invariants corresponding to local D6-D2-D0
configurations are defined applying the formalism of Joyce and Song to ADHM
sheaves on curves. A wallcrossing formula for invariants of D6-rank two is
proven and shown to agree with the wallcrossing formula of Kontsevich and
Soibelman. Using this result, the asymptotic D6-rank two invariants of (-1,-1)
and (0,-2) local rational curves are computed in terms of the D6-rank one
invariants.
