I have created multiple packages that use variables to assign Connection Manager `Expressions` such as `Connection String`. However in the new SQL 2012 [Project Deployment Model][1] I don't seem to be able to configure these variables. 

Would I therefore need to create these `Parameters` for the `Environment` and map them to specific Package `Variables`? Is this even possible and how is this done?  

[This link][2] describes configuring the `Parameters`, but not associating to **package** `Variables`.

Further to this, it seems I *could* set a Varaiable `Expression` to be a Project or Package `Parameter`, however this seems a bit convoluted. Perhaps I should stop using `Variables` altogether?

![enter image description here][3]

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Update: I've now cut-over to using Project-level and Package-level Parameters (instead of Package Variables) when I need to modify per-environment settings such as file paths and connection strings. Perhaps this was the intent from MS: any best practice advice is of course, still welcome.

  [1]: http://technet.microsoft.com/en-us/library/hh213290.aspx
  [2]: https://stackoverflow.com/a/15211591/845584
  [3]: https://i.sstatic.net/ji5Q3.png