SSIS package config vs 2012 environment variables

hi, We are using SSIS 2008 now in our project. We insert all package variables int a configuration table in Sqlserver. We are trying to migrate to SSIS 2012 and use SSISdb and environmental variables. For example in Dev if we import file from C:\dev\dev.txt we will insert that value in dev configuration table and for prd we insert prd path ex: c:\prd\prd.txt. Now in SSIS 2012 we have to configure environmental variable and I found out that it is not as simple as inserting a record in config table. Please let me know if I am missing some thing here.