This doens't really work yet, not on MTN anyway.
I didn't realise this was a new feature - got on BB only 2 days ago and thought the sync options on the MTN desktop-accessed website just looks dodgy so I skipped it. Google sync app works just fine for what I need of it. I now tried this again, but MTN gives you instructions you can't follow because of their silly WAP Email-Settings page which replaces the more proper settings app.
"If you have not already done so, to start calendar and contact synchronization, complete the security activation on your BlackBerry® device:
1. On the Home screen, click the Setup icon and click Email Accounts or Email Settings.
2. After you open the application, the security activation starts. When security activation is complete, calendar and contact synchronization automatically begins."
No kind of security activation seems to take place when you load their WAP page. That WAP page doesn't give these new sync options. Perhaps MTN still needs to propagate some upgrades on this section of the chain?