push email doesn't work SBS server R2 windows mobile 6.1

Hello I have a small business server 2003 R2 witch include sp2
and a windows mobile phone with version 6.1

I will have push email but my phone doesn't recognize it.

I can setup my phone to sync every 5 minutes but not select when item
arrives. synchronising works then fine but cost a lot of data traffic. So I
want to use push email.

I have the push email enabled in exchange server. and check all settings but
can't find anything.

I have also tried with a other mobile phone version 6.0 but just the same.

please help me!