Visual studio 2013 and .net 4.5 incompatible

I am building SSIS for SQL 2014 in VS 2013. At project creation I have defined .net 4.6.2 . I added a script task and tried adding a reference to a .net 4.5 added namespace since I need a 4.5 added new class (ziparchive). for the script language in script task I can select VB or c# versions 2012, not 2013 as the VS version is. Also, in the script task can only add reference to .net Framework 4.0 (not 4.6.2 which I selected at project creation).

Any idea how to add this reference to a .net 4.6 namespace (or minimum 4.5)?

Thank you,