selectOneMenu: noSelectionOption + <f:converter /> problem

[wcoc]

Hello, i'm using converter to object list, but i'm have a problem on submit form.

`<b:selectOneMenu value="#{agenteController.selected.fabrica}" id="fabrica" label="Fábrica"> <f:selectItem itemLabel="select fábrica" noSelectionOption="true"/> <f:selectItems value="#{agenteController.getFabricas()}" var="f" itemLabel="#{f.toString()}" itemValue="#{f}" />

                </b:selectOneMenu>

`

and receive error:

Caused by: javax.el.ELException: Cannot convert select fábrica of type class java.lang.String to class com.br.naciolog.models.Fabrica

it is bug?