Here in europe we has to use push via e-mail. The problem is that if
the phone is off for a while the mail gets in the SMS inbox and
intellisync software in the phone never gets them.
If you close your phone for a weekend (no support on weekends!!!) and
start the phone monday morning you have a lot of sms in the inbox that
you has to delete!!
And if you check your mail at the carrier all sync mail is saved in the
inbox on the mail server.

It would be nice if you could add your own carrier sms services or even
use a phone connected to the server to send sms to all your Mobile
server users!