selectManyListbox PreSelecting Values

Hi guys,

I'm new to JSP and I'm having problems PreSelecting Values in a selectManyListbox. I don't have a problem filling the selectManyListbox, the problem comes when I try to preselect items

private ArrayList listOption=new ArrayList ();

public ArrayList getListOption(){

return listOption;

}

public void setListOption(ArrayList newValue){

this.listOption=newValue;

}

private ArrayList listOptionSelected=new ArrayList ();

public ArrayList getListOptionSelected(){

return listOption;

}

public void setListOptionSelected(ArrayList newValue){

this.listOptionSelected=newValue;

}

//list of items

listOption.add(new SelectItem("1","Cheese")) ;

listOption.add(new SelectItem("2","Pickle")) ;

listOption.add(new SelectItem("3","Mustard")) ;

listOption.add(new SelectItem("4","Lettuce")) ;

listOption.add(new SelectItem("5","Onions")) ;

//list of selected items

listOptionSelected.add(new SelectItem("1","Cheese")) ;

listOptionSelected.add(new SelectItem("5","Onions")) ;