Duvida Dialog + SelectOneMenu JSF

Hello, I'm trying to open a dialog with a selectonemenu, depending on what the user selects. My SelectOneMenu is like this

<p:column headerText="Mecânica">
                    <h:commandButton>
                        <h:selectOneMenu value="#{bancoPerguntasMBean.mecanica}"
                            id="mecanica" onchange="PF('cadastraMecanica').show();"
                            rendered="#{document.type == 'Pergunta'}">
                            <f:selectItem itemLabel="Selecione a mecânica"
                                noSelectionOption="true" />
                            <f:selectItems value="#{bancoPerguntasMBean.mecanicas}" />
                        </h:selectOneMenu>
                    </h:commandButton>
                </p:column>

And my dialogue is like this

<h:form id="cadastraMecanica">
            <p:dialog style="text-align: center" header="Cadastrar Mecânica"
                widgetVar="cadastraMecanica" resizable="false" modal="true"
                width="1050" height="630">

                <p:outputPanel rendered="#{bancoPerguntasMBean.mecanica == 'QUIZ'}">
                    <ui:include src="bancoPerguntasQuestaoQuiz.xhtml" />
                </p:outputPanel>

                <p:outputPanel
                    rendered="#{bancoPerguntasMBean.mecanica == 'VERDADEIROFALSO'}">
                    <ui:include src="bancoPerguntasQuestaoVerdadeiroFalso.xhtml" />
                </p:outputPanel>

                <p:outputPanel
                    rendered="#{bancoPerguntasMBean.mecanica == 'DESCRITIVA'}">
                    <ui:include src="bancoPerguntasQuestaoDescritiva.xhtml" />
                </p:outputPanel>

                <p:outputPanel
                    rendered="#{bancoPerguntasMBean.mecanica == 'ASSOCIACAO'}">
                    <ui:include src="bancoPerguntasQuestaoAssociacao.xhtml" />
                </p:outputPanel>

                <p:outputPanel
                    rendered="#{bancoPerguntasMBean.mecanica == 'ARRASTASOLTA'}">
                    <ui:include src="bancoPerguntasQuestaoArrastaSolta.xhtml" />
                </p:outputPanel>

            </p:dialog>
        </h:form>

My question is how to correctly open the dialog, with the correct include of the file. Notice that depending on what is selected it makes a different include, but I am not able to retrieve the value selected by the user to do the validation in the dialog. Someone to give a help?

Updating

I have refactored the code to try to open the correct include, but without success, it follows refactoring

<p:column headerText="Mecânica" style="text-align: center">
                                    <p:selectOneMenu id="mecanicas"
                                        value="#{bancoPerguntasMBean.mecanicaSelecionada}"
                                        required="true" widgetVar="sel"
                                        onchange="PF('modalMecanica').show(); getMecanicaSelecionada()"
                                        rendered="#{document.type == 'Pergunta'}">
                                        <f:selectItem itemLabel="Selecione a mecânica" itemValue=""
                                            noSelectionOption="true" />
                                        <f:selectItems value="#{bancoPerguntasMBean.mecanicas}"
                                            var="mecanica" id="mecanica" itemValue="#{mecanica.nome}"
                                            rendered="#{mecanica.nome != 'IMAGEM RESPOSTA'}"
                                            itemLabel="#{mecanica.nome}" />
                                    </p:selectOneMenu>
                                </p:column>

Here the dialog

    <h:form id="modalMecanica">
                            <p:dialog style="text-align: center" header="Cadastrar Mecânica"
                                widgetVar="modalMecanica" resizable="false" modal="true"
                                width="1050" height="630">
                                <p:outputPanel
                                    rendered="#{bancoPerguntasMBean.mecanicaSelecionada == 'QUIZ'}">
                                    <ui:include src="bancoPerguntasQuestaoQuiz.xhtml" />
                                </p:outputPanel>

                                <p:outputPanel
                                    rendered="#{bancoPerguntasMBean.mecanicaSelecionada == 'VERDADEIRO FALSO'}">
                                    <ui:include src="bancoPerguntasQuestaoVerdadeiroFalso.xhtml" />
                                </p:outputPanel>

                                <p:outputPanel
                                    rendered="#{bancoPerguntasMBean.mecanicaSelecionada == 'DESCRITIVA'}">
                                    <ui:include src="bancoPerguntasQuestaoDescritiva.xhtml" />
                                </p:outputPanel>

                                <p:outputPanel
                                    rendered="#{bancoPerguntasMBean.mecanicaSelecionada == 'ASSOCIACAO'}">
                                    <ui:include src="bancoPerguntasQuestaoAssociacao.xhtml" />
                                </p:outputPanel>

                                <p:outputPanel
                                    rendered="#{bancoPerguntasMBean.mecanicaSelecionada == 'ARRASTA SOLTA'}">
                                    <ui:include src="bancoPerguntasQuestaoArrastaSolta.xhtml" />
                                </p:outputPanel>
                            </p:dialog>
                        </h:form>

The dialog opens correctly, however empty, it is not performing any include. In the bean I created an attribute that receives the selected face

private String mecanicaSelecionada;