Back on BB: IMAP/BIS security question

Hi Folks,

Back to BB from iPhone.

I've set up a 9930 on hosted BES with several additional IMAP accounts. Struggling with lack of full sync on gmail (compared to iPhone), but I can live with it.

Can someone tell me if the IMAP accounts are run using the BIS? If so, is the security/encryption routed through the NOC as with my BES account? My understanding is that while the BES account is the most secure, the BIS (IMAP??) accounts are secure to a certain level.

Is this an improvement over the Active-sync I used on the iPhone? I'm hoping it is, because the trade off in IMAP sync efficiency would be worth the bump in email security.

Also, is all internet traffic (browsing, etc) originating on the BB handset handled by the BIS?

Or have I got it wrong?

Thanks for the help.