An Execute Process Task could work as well. I have done similar things by building my command line arguments dynamically in a variable using an Expression and then mapping the variable to the Arguments property of the Execute Process Task. The Task can be frustrating before getting the properties set correctly, but once you get it the technique is reliable. Make sure to set Working Dir to plink's home dir or fully qualify the path to plink.exe in the Executable property.

If you go with a Script Task Google for examples on how to use the .NET class System.Diagnostics.Process.