The BES won't actually deliver the entire file to your device - it will convert it to some format (mostly txt) that is MUCH smaller. So you COULD do it. And depending on the version of the BES (4.1.3 has a better attachment service) and the verison of the handheld OS (4.2 I dont know much about), it might look just fine.

Besides, if you have EDGE coverage it should convert reasonably quick for you.