HOW can you use it to upgrade to C7 pro??

 I tried entering the MAGAZINE S/N directly on Daz registration- it came back as invalid (triple checked it). It does work to install the program.

  I submitted a Cust Service question- and some suggested solutions came back-including a link- when I clicked it it gave me a Carrara Pro FIVE S/n!
Which I already bough retail from Eovia

  Since people HAVE used it to upgrade- HOW did they do so??

Any help from those folks appreciated!