@ManagedProperty(name = "guestbookBacking", value = "#{guestbookBacking}")
protected GuestbookBacking guestbookBacking;
public void add() {
Entry entry = new Entry(EntryUtil.create(0L));
LiferayFacesContext liferayFacesContext = LiferayFacesContext.getInstance();
entry.setGroupId(liferayFacesContext.getScopeGroupId());
entry.setGuestbookId(guestbookBacking.getSelectedGuestbook().getGuestbookId());
guestbookBacking.setSelectedEntry(entry);
guestbookBacking.editEntry();
}