SQL Server 2012 software and licencing

Hi folks,

We've purchased some per core licences for a SQL 2012 install.

When I try to install SQL 2012 I get asked to put in a licence key or choose evaluation, but all we have is paperwork proving the purchase of the licences, we were told we wouldn't be provided with a key.

The only way I know of to install the software without needing a key is if I download a copy from MSDN.

Am I OK to use an MSDN copy in production if we have the paper licences or should we be using a different software source?

If we can't are there copies of the SQL software available that doesn't need a key and is specifically for the above situation?

Thanks for any help on this,

Regards,