I'm not in front of my Mac at the moment, but isn't there a setting somewhere in Preferences that you can choose which app to open when you plug-in a digital camera or hit the scan button on a scanner? I swear I saw it somewhere a while back ... I'll try and find it again ...
OK - I'm on my Mac now ... Image Capture in the Applications folder - go into Preferences - then you can choose which app to open when you connect a digital camera.
After re-reading the original post, it doesn't solve your problem agusgriego, but it might help mindbend ... I have an A80 myself, but I also have a card reader, which I find abundantly more convenient than hooking up the cable to the camera so I've not run into this problem. I tested it out though tonight, and see what you mean.