VLSC : SQL Licencing-ProductKeys

Hi There

I downloaded Sql Server 2014 Standard from TechNet Evaluation center.

Now we have VLSC login and ONLY need key to activated as we have already installed Sql server which is in production.

However when tried to get the key for Sql in VLSC, it prompts that no key is required for the product.

How can I activate Sql server , which has been downloaded from TechNet Evaluation center.

Thanks in Anticipation