How to get Database item for Descriptive flexfield.

we are looking for Database item for descriptive flexfields (PER_DRIVERS_LICENSE_TYPES_DFF). we got to know a process to create DBI for flexfield. These are the steps we followed to run that process (Payroll -> flow submission & result -> submit a process or result -> Generate Flexfield Database Items), while adding Parameter details (Name and Context) in flow, parameter name is taking only seeded DFFs not custom DFFs.

Can you please guide us how to get DBI for Attributes present in above driving license DFF