Hi Christopher,
I am also running into the same issue. Below are some more details .
Even after populating all values to P0001 Data is not read from Buffer. Upon further analysis found generic service is calling CL_HRPA_UI_CONVERT_0007_XX which in turn calling below class where the buffer mode is passed a 'W' i.e. Write to Buffer . I think this should be 'R' Which is Read from Buffer. Could you please share your inputs.
Regards,
Krishna