No update statement is issued

Hey,
This snippet runs under a method annotated with @Transactional

Code:

---

for (Group detachedGroup : groups) {
    Group group = groupDao.load(detachedGroup.getId());
    outBox = sendMessageToGroup(usr, group, text, language);
    groupDao.save(group);
}

---

sendMessageToGroup() increases the Group's internal counter and the save() method of GroupDao employs Session.saveOrUpdate() method.
The problem is no update statement is issued after the previous statement and the whole method is done.
Any ideas why?
Spring 2.5 , Hibernate 3
Thanks.