leading zeros truncated

I'm using JTOpen to do point-to-point integrations between our iSeries server 
and a PeopleSoft application server running on Microsoft.
 
One thing we want to do is invoke Java classes that read DB2 physical files on 
the iSeries and create fixed with text files on the PeopleSoft server. I'm 
using record-level access to do this, and have succeeded in coding Java classes 
that create CSV files and XML files. But the fixed width format is giving me 
problems. It seems signed or packed fields in DB2 files have their leading 
zeros truncated. This frameshifts the record in the fixed width file.
 
Below is the exact code I'm using. Any ideas on what I'm missing? Is the 
truncation forced by JTOpen? Is the truncation forced by the Object.toString() 
method? Any way to work around this (other than making sure the DB2 file only 
contains character fields)?
 
Thanks in advance for any help.
Kelly
 
/* Establish a connection with the iSeries. */
AS400 system = new AS400(systemName, user, password);
      
String filePath = (new QSYSObjectPathName(db2Library, db2File, 
"FILE")).getPath();
SequentialFile file = new SequentialFile(system, filePath);
system.connectService(AS400.RECORDACCESS);
      
/* Get the record format of the DB2 file. */   
RecordFormat format = (new AS400FileRecordDescription(system, 
filePath)).retrieveRecordFormat()[0];
String fields[] = format.getFieldNames();
file.setRecordFormat(format);
 
/* Generate the fixed width text file from the DB2 file. */   
File theFixFile = new File(fixFile);
PrintWriter txtOut = new PrintWriter(new FileWriter(theFixFile));
file.open(AS400File.READ_ONLY, 0, AS400File.COMMIT_LOCK_LEVEL_NONE);
Record record = file.readNext();
while (record != null){
    for (int i = 0; i < fields.length; i++){
        rawData = record.getField(i);
        fieldData = rawData.toString();
        recordLine = (recordLine + fieldData);
    }//end-for
    txtOut.println(recordLine);
    recordLine = "";
    record = file.readNext();
}//end-while
txtOut.close();
file.close();
    
/* Disconnect from the iSeries. */
system.disconnectService(AS400.RECORDACCESS);