iSeries: SQLRPGLE How to call a procedure for each record in a SELECT statement

Within an SQLRPGLE program I need to run an insert into statement to copy some records to another file having copied records assigned a new record ID. To do so I followed these steps:

1) Prototype a procedure to get a new record ID each time is called

    D ri_box12        PR            13S 0
    D   wkFileName                  10A   Value
    

2) Execute a dynamic SQL statement

    C                   EVAL      SQL_STM='insert into PGMR46/STD05GR0F'
    C                                    +' (select CART, CARV, '
    C                                    +%char(ri_box12('STD05GR0F'))
    C                                    +'  from arasso0f)'
    C/EXEC SQL
    C+ execute immediate :SQL_STM
    C/END-EXEC
    

3) Define ri_box12 procedure

    P ri_box12        B
    D ri_box12        PI            13S 0
    D   wkFileName                  10A   Value
    D   wkID          S             13S 0
    C                   DO

    ** ...some instructions to give wkID a value
    C                   ENDDO
    C                   Return    wkID
    P                 E
   

The point is that ri_box12 is called only once, so all copied records have the same ID; multiple runs of the program again copy all records with a new record ID.

What did I do wrong or what am I missing?

Than you very much