Resolves an identity by its external id (NumExtern) and name (no password).

POST /api/v1/identity/login/externalIdName

SOAP Equivalent: ACP_IdentityLoginWithIDExternAndName (and its family-filtered variant).

SOAP to REST Field Mapping

REST Field	SOAP Field	Notes
externId	idExtern	External identity id (NumExtern transcoding)
name	identityNom	Identity name (plain upper-case match)
firstName	identityPrenom	"NULL"/"COMPANY" fall back to the record surname
family	FAMILY family	Optional family filter

Unresolved external id / name => HTTP 404 (SOAP 10504).