[postgis-users] Missing Portuguese CRS on Spatial_ref_sys

[Fonseca Hespanha de Oliveira, Joao da]

I am doing some CASE tool research with PostGIS as main 'data repository'.
My test data is Portuguese Cadastral digital data set, which, together with the Orthophoto Map series from IGP (Civil Mapping Agency from Portugal) uses a CRS that is not listed in the spatial_ref_sys table. It is close to the SRID=27492, the main difference lies on the false origin amounts. Here is the definition from ESRI (titled 'Datum_73_Hayford_Gauss_IGeoE'):

Projection: Transverse_Mercator
False_Easting: 200180,598000
False_Northing: 299913,010000
Central_Meridian: -8,131906
Scale_Factor: 1,000000
Latitude_Of_Origin: 39,666667
Linear Unit: Meter (1,000000)

Geographic Coordinate System: GCS_Datum_73
Angular Unit: Degree (0,017453292519943299)
Prime Meridian: Greenwich (0,000000000000000000)
Datum: D_Datum_73
  Spheroid: International_1924
    Semimajor Axis: 6378388,000000000000000000
    Semiminor Axis: 6356911,946127946500000000
    Inverse Flattening: 297,000000000000000000

My question is how to properly add this new CRS, and define a new SRID, into the spatial_ref_sys table?

Note: I have checked also the EPSG v6.14 data for PostGRE_SQL, but it had not this CRS definition either.