Problem getting Return Parameter

I am trying to get a return Parameter from a variable that is changed in
a CL program. My code looks as following

AS400Text text3 = new AS400Text(5); 
byte[] parm3 = text3.toBytes(milesParm); 
parameterList[3] = new ProgramParameter(parm3);

THEN I call the program

byte[] getMiles = parameterList[3].getOutputData();
milesParm = getMiles.toString();

Fairly new to this so not sure that I am even trying to do this the
correct way can someone point me in the right direction??

Thanks,

John Sutor