call subprocedure in SQL

Hello,

Does anyone have any examples on how to call a subprocedure from an
embedded SQL statement?
I'd like to call a subprocedure with parameters(FHDDAT, FHPUDT, FLD1, FLD2).  
This subprocedure will take calculate values for FLD1 & FLD2 based on
the FHDDAT & FHPUDT parameters.

Below is my working SQL statement:
=============================================================
SELECT FHOT, FHPRO, FHDT, FHDDAT, FHDTIM, FHDADT, ' +
      'FHPUDT, FHSCD, FHCCD, FHCCT, FHCST, FHCZIP ' +
 'FROM FRL00144 WHERE FHDDAT >= ' + %CHAR(FDATE)    +
                ' AND FHDDAT <= ' + %CHAR(TDATE)    +
                ' AND FHDT   <> ' + %CHAR(NUM#OT1)  +
                ' AND FHOT   =  ' + %CHAR(NUM#OT1)  +
                ' AND FHDT   =  ' + %CHAR(NUM#ODT)  +
                ' ORDER BY FHOT, FHDT'              +
                ') WITH DATA';
=====================================================

Thanks,

Frank