FUNCTION CheckPassword(
    Login_ IN USERS.USER_LOGIN%TYPE,
    Password_ IN USERS.USER_PASSWORD%TYPE,
    UserId_ OUT USERS.USER_ID%TYPE
) RETURN VARCHAR2;

<?xml version="1.0" encoding="utf-8"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
  assembly="myassembly" namespace="myassembly.mynamespace">
  <sql-query name="SP_CheckPassword" callable="true">
  <query-param name="Login_ " type="string" />
  <query-param name="Password_ " type="string" />
        begin cpa.CheckPassword(:Login_ , :Password_ , ???); end;
  </sql-query>
</hibernate-mapping>