Using HERWIG5.9 I generated 10K  CC DIS  e+p interactions (iproc=19010) with  the HERA kinematics, in the range Q2> 200 GeV^2.
The proton structure function used corresponded to the CTEQ 4D set.
The generator level cross section is:

                                                         Sigma = 31.2 +- 0.2 pb
 
 

 
The number of events corresponded to a luminosity L=292.7 pb-1. Rescaling to the luminosity integrated by ZEUS  in 1994-1997 (Lz=46.6 pb-1) we expect approximately 74 D*(2010)+,  200 D0 and 117 D+ .
We assume an average efficiency of 0.7 to  identify and reconstruct a CC event at Q2 > 200 GeV^2.

Considering the decay D*(2010)+ ---> D0 pi  (D0->K- pi),  [Br=0.683 x 0.0385 = 0.026],  without any selection cut on the tracks we would expect rouglhy 2 D* .

Considering the decay D0 -> K- pi , we would expect roughly 8 D0, again without any selection cut, and approximately 4-5 D+.

In this  plot  we show the generator level invariant masses (K- pi) and (K- pi pi) [no momenta smearing]. The first row shows the masses assuming a perfect particle identification. In the second row the upper plots are repeated assuming no particle id.
The figure is repeated using the realistic statistic of 1000 events  here .