If you are on WebDynpro FPM, here are the changes to make.
1. Copy the FPM component configuration for this UIBB
2. Add the custom field as column if you don't find the appropriate field from the list of fields. There are more than 10 custom fields.
3. Fill the custom fields in the feeder class CL_HRESS_PTARQ_LEAVREQ_GUIBBL by implementing enhancements.