Rogers Tethering on BB Z10 + Outlook 2010 over RPC

Hello,

Our BBs are connected via BES10.

I can tether to Rogers with the USB cable - with almost no problem. The only problem that I have is, Outlook 2010 connected over HTTP/RPC will not connect when it's tethered. My Outlook client works just fine on all other networks, so I know Outlook is configured and working properly.

Has anyone else seen this?

Is there any ports that Rogers is blocking via the tethering process? This is the only problem I have when tethering.

Thanks
Neil