One-to-many JPA EntityManager Primefaces

Question

I have the following form inside a dialog:

<h:form id="CommentCreateForm">

            <h:panelGroup id="display">

                <p:outputPanel id="commentsPanel">

                    <p:row>
                        <p:column>
                            <p:inputTextarea id="commentText" value="#{commentsController.selected.commentText}" cols="100" rows="20" style="margin-bottom:10px"/>
                        </p:column>
                    </p:row>

                </p:outputPanel>

                <p:commandButton actionListener="#{commentsController.savePropReception}" value="#{myBundle.Save}" update="display,:PmMainListForm:datalist,:growl" oncomplete="handleSubmit(xhr,status,args,PF('CommentCreateDialog'));">
                    <p:confirm header="#{myBundle.ConfirmationHeader}" message="#{myBundle.ConfirmEditMessage}" icon="ui-icon-alert"/>
                </p:commandButton>

            </h:panelGroup>

        </h:form>

With it's corresponding parent entity called Comments:

@Entity
@Table(name = "comments")
@XmlRootElement
@NamedQueries({
    @NamedQuery(name = "Comments.findAll", query = "SELECT c FROM Comments c")
    , @NamedQuery(name = "Comments.findByCommentText", query = "SELECT c FROM Comments c WHERE c.commentText = :commentText")
    , @NamedQuery(name = "Comments.findByIdComments", query = "SELECT c FROM Comments c WHERE c.idComments = :idComments")})
public class Comments implements Serializable {

private static final long serialVersionUID = 1L;
@Size(max = 2147483647)
@Column(name = "comment_text")
private String commentText;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "id_comments")
private Long idComments;
@OneToMany(cascade = CascadeType.ALL, mappedBy = "propReceptionComment")
private List<PmMain> pmMainCollection5;

[... Getters and Setters ...]

public void setPropReception(PmMain pmMain){
    pmMain.setPropReceptionComment(this);
    pmMainCollection5.add(pmMain);
}

And it's child entity called PmMain:

@Entity
@Table(name = "pm_main")
@XmlRootElement
@NamedQueries({
    @NamedQuery(name = "PmMain.findAll", query = "SELECT p FROM PmMain p")
    , @NamedQuery(name = "PmMain.findByPropId", query = "SELECT p FROM PmMain p WHERE p.propId = :propId")
    , @NamedQuery(name = "PmMain.findByPropName", query = "SELECT p FROM PmMain p WHERE p.propName = :propName")
    , @NamedQuery(name = "PmMain.findByPropStatus", query = "SELECT p FROM PmMain p WHERE p.propStatus = :propStatus")
, @NamedQuery(name = "PmMain.findByIdPmMain", query = "SELECT p FROM PmMain p WHERE p.idPmMain = :idPmMain")})
public class PmMain implements Serializable {

private static final long serialVersionUID = 1L;
@Size(max = 25)
@Column(name = "prop_id")
private String propId;
@Size(max = 125)
@Column(name = "prop_name")
private String propName;
@Size(max = 25)
@Column(name = "prop_status")
private String propStatus;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "id_pm_main")
private Long idPmMain;
@JoinColumn(name = "prop_reception_comment", referencedColumnName = "id_comments")
@ManyToOne
private Comments propReceptionComment;

[... Getters and Setters ...]

And the CommentsController contains a method called savePropReception:

public void savePropReception(){

    PmMain pmMain = new PmMain();
    Comments comments = new Comments();

    pmMain.setPropReceptionComment(comments);

    comments.setPropReception(pmMain);

    commentsFacadeEJB.edit(comments);

}

While commentsFacadeEJB contains:

public void edit(T entity) {
    getEntityManager().merge(entity);
}

So, when a PmMain is already created, I can't get PmMain.propRecetionComment to update with the ID of a new 'Comments'. What am I missing?