Problem with OWA and Treo 650 thru Sprint

[DJ_JONES]

Looking for some help here. I am an IT Manager who got handed this little phone project.
We recently put in service about a dozen Treo 650's. I am running Exchange 2003 and OWA. About half the phones are on Cingular Service and they work just fine and the OWA has no problems. The other half are on Sprint Service and access the INternet fine but when trying to access the OWA they get an error "Unknown Authentication Type".
I called Sprint and got the deer in the headlights look going on with them and they pretty much told me "It just may not work with out service".
ANyone have this problem? ANy ideas how to fix it?

THanks
DJ

[paradoxar]

DJ, I was wondering if you can help me with the following questions, how the users are receiving the OWA emails thru Cingular. Are those users using the Cingular webclient to configure and retrieve the emails from the exchange OWA?

I am trying to identify what cell provider support the OWA option since that will be the only way to retrieve my emails from work. So far I found tha T-Mobile supports Corporate Mail retrival by setting it up in their webclient "my-email", but I alredy have an account with Cingular that I am trying to keep

Thanks in advance for your response