The Wrapper (1)
ufunction f_wrapper_cl (i_id_nr,
v1_tx varchar2:=null,...,v5_tx varchar2:=null)
ureturn CLOB is
u  v_out_cl CLOB;
u  v_sql_tx varchar2(2000);
u  v_rec t_extra_ui%rowtype;
ubegin
u  select * into v_rec from t_extra_ui where id_nr=i_id_nr;   
u
if v_rec.v1_label_tx is not null then
u    v_sql_tx:=nvl(v_rec.v1_convert_tx,':1');
u  end if;
u  ...
u  if v_rec.v5_label_tx is not null then            
u    v_sql_tx:=v_sql_tx||','||
u       nvl(v_rec.v5_convert_tx,':5');
u  end if;