Passing paramater to validator of composite component - jsf-2

Question

I am using Mojarra 2.3.0.
I have a composite component which contains an inputText. I want to be able to validate this inputText using a FacesValidator. Furthermore I want to pass certain parameters to the validator.
My Composite component is defined this way:
<composite:interface>
...
<composite:editableValueHolder name="inputValidator" targets="value" />
...
</composite:interface>
<composite:implementation>
...
<h:panelGroup layout="block" styleClass="col-sm-10">
<h:inputText id="value"
disabled="#{cc.attrs.disabled}"
value="#{cc.attrs.value}"
styleClass="form-control"
required="#{cc.attrs.required}"
onchange="#{cc.attrs.onChange}"
/>
</h:panelGroup>
...
</composite:implementation>
I use the component this way and declared a f:validator and f:attribute (which should be passed to the validator)
<uiComps:field labelText="add language"
id="languages"
autocompleteValues="#{ocrEngineViewModel.getAllSupportedLanguages()}" >
<f:ajax event="onChange" listener="#{ocrEngineViewModel.updateSelectedLanguages}" render="newParameter:languages:value newParameter:usedLanguages" />
<f:validator validatorId="OcrLanguageValidator" for="inputValidator" />
<f:attribute name="allSupportedLanguages" value="#{ocrEngineViewModel.allSupportedLanguages}"/>
</uiComps:field>
<h:message for="languages" />
My validator looks like this:
#FacesValidator("OcrLanguageValidator")
public class OcrLanguageValidator implements Validator {
#Override
public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
Object allSupportedLanguages = component.getAttributes().get("allSupportedLanguages");
throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR, "lala", "not good"));
}
}
There are two problems:
The parameter "allSupportedLanguages" (which is a List<String>) is null when I try to retrieve it in the validator.
The ValidationException which holds a FaceMessage is not displayed in the message area for the component. I don't see any information about the message on the page.
Update:
Instead of the composite component I put the code directly into my page.
<h:panelGroup layout="block" styleClass="col-sm-10">
<h:inputText id="value" styleClass="form-control">
<f:ajax event="change" listener="#{ocrEngineViewModel.updateSelectedLanguages}" render="newParameter:languages:value newParameter:usedLanguages" />/>
<f:validator validatorId="OcrLanguageValidator"/>
<f:attribute name="allSupportedLanguages" value="#{ocrEngineViewModel.allSupportedLanguages}"/>
</h:inputText>
</h:panelGroup>
This works and I see the attribute in the validator. So I guess the problem lies in the usage of the composite component.
Update2:
I was able to solve the validation error message problem. I placed the <h:message for="value"/> inside the composite component.