Can I use my iPhone 2G with Bell Canada?

Long ago, I purchased an iPhone 2G in the US before Rogers came to Canada to provide iPhone service. Before I got my 3GS, I had unlocked it and was using it with my Rogers SIM with no problem.

Recently my wife took an interest in the handset and we took it to the Bell Store to have them try to get the device working with her account.

The sales person at the kiosk tried a "Demo SIM", and when they did that the device read "Invalid SIM".

Is there any reason to believe that we can get an older iPhone 2G working with Bell Canada? Maybe the salesperson just have some older SIM card perhaps that doesn't work with the 2G? Or is this a known limitation?

It is not compatible.

Bell's new network (shared with Telus) is a 3G HSPA overlay (on top of their existing CDMA network) which the iPhone 2G does not support.