Camel Session thread functions disabled in Tinymail?

[tinymail mexon spamgourmet com]

(Congratulations on 1.0.0, by the way!)

I'm working in Modest, trying to turn on camel's functionality for 
keeping IMAP folders synchronised.  I've bumped up against this function:
static void *
tny_session_camel_ms_thread_msg_new (CamelSession *session, 
CamelSessionThreadOps *ops, unsigned int size)
{
	CamelSessionThreadMsg *msg = ms_parent_class->thread_msg_new(session, 
ops, size);
	msg->ops = g_new0 (CamelSessionThreadOps,1);
	msg->ops->free = my_free_func;
	msg->ops->receive = my_receive_func;
	msg->data = NULL;
	msg->op = camel_operation_new (my_cancel_func, NULL);

	return msg;

}

In Camel Disco, the function cdf_folder_changed gets called when new 
messages turn up in the folder.  This tries to set up a thread to run 
cdf_sync_offline to synchronise the mails.  It passes this function 
inside a CamelSessionThreadOps object to camel_session_thread_msg_new, 
which calls tny_session_camel_ms_thread_msg.
So it calls thread_msg_new which calls session_thread_msg_new which sets 
up the msg correctly.  But as you can see, it overwrites the ops member 
with its own CamelSessionThreadOps object, pointing to empty functions 
my_free_func and my_receive_func.  So the supplied functions never get 
called.  This seems odd.
I commented out all those msg->* lines and folder synchronisation seems 
to work.  So I'm wondering if there's some reason for that stuff being 
there, and if I'm breaking anything with this?