Is it possible to register Cubase 3 SE with Soft-eLicenser?

A few years ago I bought Cubase 3 SE. Next I updeted it to Cubase 5 Essential and naxt to Cubase 6 Artist. But last week when I moved out I lost my eLicenser somewhere. I know I can buy a new eLicenser but I know too that I can use Soft-eLicenser (I hope I’m right). But when I enter Cubase 6 activation code I need to enter Cubase 5 code and when I enter Cubase 5 code I need to activate Cubase 3 first. But… Cubase 3 has only 10-numer serial key. What should I do?

You are wrong. You need the USB eLicenser. And again you can not simply buy a new USB eLicenser, since the license got lost with your old one. Unless you registered your old USB eLicenser with Steinberg, you might have to buy a new License, otherwise they might replace your lost license. Anyway you should contact Steinberg support