I Cannot Upgrade Cubase Elements 6 to Cubase artist 7,

Help me, Please!
I cannot upgrade Cubase Elements 6 (full version, I bought it on Steinberg website) to Cubase Artist 7 (also I bought it on the Steinberg website) I have not Usb-licenser. When I tried enter activation code for Cubase Artist 7 (after installiation, course) My Soft-elincer wrtite me message: “NO LICENSE TO UPGRADE SELECTABLE”

Cubase 6 Elements works with eLicenser (Steinberg key)or soft-eLicenser, Cubase Artist 7 only with eLicenser.

So you have to buy a key, transfer the license to the key and then it should be possible to upgrade the license.