If it helps anyone, I successfully used the following:
Code:
<class name="Star" table="STARS">
    <id name="id" column="id"/> <!-- Long -->
    <property name="name"/> <!-- String -->
    <property name="mass"/> <!-- Double -->
    <loader query-ref="loadStarSP"/>
    <sql-insert check="none" callable="true">{call USER1.createStarHB (?, ?, ?)}</sql-insert>
    <sql-update check="none" callable="true">{call USER1.updateStarHB(?,?,?)}</sql-update>
    <sql-delete check="none" callable="true">{call USER1.deleteStarHB(?)}</sql-delete>
</class>
<sql-query name="loadStarSP"  callable="true">
    <return class="Star"/>
    { ? = call USER1.loadStarHB(?)} 
</sql-query>
<sql-query name="selectAllStars"   callable="true" >
    <return  class="Star"/>
    { ? = call USER1.selectAllStars()} 
</sql-query>
Code:
CREATE OR REPLACE FUNCTION loadStarHB(  in_id in STARS.ID%type)
RETURN SYS_REFCURSOR  AS  
    st_cursor SYS_REFCURSOR;  
BEGIN  
  OPEN st_cursor FOR  
    SELECT *  FROM STARS WHERE  ID = in_id;  
  RETURN  st_cursor;  
END;  
CREATE OR REPLACE PROCEDURE createStarHB(
    in_name in STARS.NAME%type,
    in_mass in STARS.MASS%type,
    in_id in STARS.ID%type)
AS
BEGIN
  INSERT INTO STARS (NAME, MASS, ID) VALUES ( in_name, in_mass, in_id );
END;
CREATE OR REPLACE PROCEDURE updateStarHB(
    in_name in STARS.NAME%type,
    in_mass in STARS.MASS%type,
    in_id in STARS.ID%type)
AS
BEGIN
  update STARS set
    NAME=in_name, MASS=in_mass
  where ID=in_id;
END;
CREATE OR REPLACE PROCEDURE deleteStarHB(
  in_id in STARS.ID%type
) AS
BEGIN
  delete from STARS where ID=in_id;
END;
CREATE OR REPLACE FUNCTION selectAllStars()
    RETURN SYS_REFCURSOR
AS
    st_cursor SYS_REFCURSOR;
BEGIN
    OPEN st_cursor FOR
 SELECT *
 FROM STARS;
      RETURN  st_cursor;
 END;