  We study possible contributions to the Ds^+ -> omega pi^+ and Ds^+ -> rho^0
pi^+ decay amplitudes. The Ds^+ -> omega pi^+ decay amplitude vanishes when the
naive factorization is used, while the Ds^+ -> rho^0 pi^+ decay amplitude
arises due to the annihilation contribution. We find that amplitudes for both
decays might be a result of the internal K, K^* exchange. The Ds^+ -> omega
pi^+ amplitude might obtain additional contribution from Ds^+ -> rho^0 eta
(eta') re-scattering. The low experimental bound on the Ds^+ -> rho^0 pi^+ rate
can be understood as a result of combination of the pi(1300) pole dominated
annihilation contribution and the K,K^* internal exchanges. The calculated
branching fractions for Ds^+ -> omega pi^+ and Ds^+ -> rho^0 pi^+ are in
agreement with the current experimental results.
