Okay, I finally found my old notes from the last time I did this in SME9x and it was just a matter of enabling ActiveSync.
[root@smeserver-10 ~]# config setprop horde ActiveSync enabled
[root@smeserver-10 ~]# signal-event email-update
[root@smeserver-10 ~]# config show horde
So now that it is enabled I will have to test it but I think it should work fine now.
Very handy for smartphone users.
-edb