B^0_s->D^{+-}_s K^{-+} and B^0_s->D^-_s pi^+ event selection

The decay channels Bs->DsK and Bs->DsPi are used to extract the physics parameters Dm_s, DGamma_s and gamma+phi_s. Simulation studies showed that with one year of data taking a total of (82+-26)k Bs->DsPi and (5.4+-2.2)k Bs->DsK events are reconstructed, triggered and selected. The B/S for Bs->DsPi originating from B-inclusive events is expected to be (0.32+-0.10), while for Bs->DsK a 90% CL upper limit for the B-inclusive background is obtained: B/S <0.5. For Bs->DsK an extra source of background, Bs->DsPi, gives an additional contribution to B/S = (0.111+-0.056)%.