Java Development Tools

Hi ,
I am using jdeveloper version 11.1.1.6.0.
I have an select one choice which is loaded with the list of values from the bean as follows:

                  <af:selectOneChoice 
                                value="#{bindings.AfCmnLovMasterListVO.inputValue}"                              
                                autoSubmit="true"
                                contentStyle="height: 20px;width:130px;"
                                required="#{bindings.AfCmnLovMasterListVO.hints.mandatory}"
                                shortDesc="#{bindings.AfCmnLovMasterListVO.hints.tooltip}"
                                simple="true" id="socMaterial"
                                valueChangeListener="#{AfOrdCtrBulkQuoteReqBean.custMaterialMaterialValueChangeListener}"
                                      binding="#{AfOrdCtrBulkQuoteReqBean.socMaterial}">                
                <f:selectItems value="#{bindings.AfCmnLovMasterListVO.items}"
                                 id="si3"/>
                </af:selectOneChoice>

I want to programatically create value change event and change the value of the select one choice.
Changing of select one choice is done by following code

                            RichTable objMaterialTable = (RichTable) JSFUtils.findComponentInRoot("socMaterial");
                            objMaterialTable.setValue(new String("CaF2"));   //Not working with this
                            objMaterialTable.setValue(new Integer(5));   //Working with this

objMaterialTable.setValue(new String("CaF2")); why this doesnt work.

and also objMaterialTable.setValue(new Integer(5)); this works but does not fire valueChangeListener
so how i can set the value in before phase method and also fire the valueChangeListener