Sophie's vet said the ears should be taped up around 8-9 weeks. He shaved her ears, placed a small roll of gauze inside the ear for support, put a few pieces of tape around each ear, and then one longer piece of tape around both ears to hold them straight up. She looked like batman!
He said it takes around 6 days for the cartlidge in the ears to firm up, so he said not to remove the tape until the 6 or 7th day. It worked like a charm!!
I think I have a pix of Sophie with her ears taped in my photo album, so you might want to check it out. If not, I'll add one soon.