Dear Miguel,
The enable_user_poa option is not available for the pvwattsv5 compute module. That was probably an oversight when we developed the new module. I have added that as a requested new feature for a future version.
In the meantime, you can use POA irradiance as input to the pvsamv1 module. To do that set irrad_mode = 3 for POA irradiance data measured using a reference photovoltaic cell, or irrad_mode = 4 for POA data measured using a pyranometer. Then, add a "POA" column to a weather file formatted using the SAM CSV Format containing the POA data. The model will then ignore any other irradiance data in the file, and use your POA data as input to the module model.
Best regards,
Paul.