All you need to do is go in the camera's menu system and make sure that it's set up correctly. Not sure if that would be MTP or UMS, but try either one. As for the proprietary Canon software, I'm sure it's just fine. Go to the Canon website and download the updated drivers or software. They must have updated those things for Lion.
Aside from that, all you really need to do, like you've already said, is put the SD card into the SD card slot of your Mac OR use an external card reader. It's really best to do it in those ways rather than plugging the camera in directly anyway, because there's a better chance of data corruption happening the former way.
Image Capture is a great tool, btw.
Doug