Very Computer

Haveing trouble getting Smart Phones to function with
Ex2003.  The OMA works fine, but it won't sync or send
SMS.  I have a test env.  Just Ex2003 on Win2003.net on
the DMZ with all ports open.  The phone just doesn't see
the server.  What am I missing? Do I need SSL certs? Is
there a step I missed in setting up the user on Ex2003?  
Or a set up on teh client??  Please help!!
Thanks,
Aaron