Correct way to update 6.4 to 7.3 via FTP

Hi all, I'm no to this list, so hello to everyone. I've installed Suse 6.4 on a Umax Clone (Apus 3000). Now I would like to update to 7.3 via FTP. Can anyone tell me the right way to do this? There are two ways I already tried to no avail: The sdb suggests to download the 7.0 installer. This way I could start the installation but it stopped in the middle of the installation. I let it run overnight but it did not finish nor time out. The readme on the ftp server suggests downloading bootx 1.2.2 and a kernel called install-oldworld. This gives me a crash when trying to boot. Any hints would be greatly appreciated. Ole