I've successfully duplicated your solution, except I did it in a .net web form. My project is using the 4.0 .NET framework.

I tried to reproduce your solution in SSDT ,--here is what happened--

I am using VS 2012, so my IDE didn't behave exactly like yours did. . I tried to add the EPPPlus to the GAC, but can't even find the GAC utility on my machine. So I simply set it up as a reference, and with the line "Dim p As New ExcelPackage(newFile)" as part of the code (no other code from the example afterwards), I get a DTS Script Task runtime error.

When I change the Target .NET framework to 3.5, the lines "<Microsoft.SqlServer.Dts.Tasks.ScriptTask.SSISScriptTaskEntryPointAttribute()> _

<System.CLSCompliantAttribute(False)> _

Partial Public Class ScriptMain

Inherits Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTARTScriptObjectModelBase" is underlined with warnings "Type Microsoft.SqlServer.Dts.Tasks.ScriptTask.SSISScriptTaskEntryPointAttribute is not defined" and "Type Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTARTScriptObjectModelBase" is not defined"

It seems that the EPPlus dll is a great tool. Tricky to get set up in SSIS, and I'm investigating how to get it working in 2012 SSIS, using the .net framework 4.0. I'd like to be able to just copy my code from the code behind of the webform, but seems the complexities of the microsoft solutions are making it difficult (or, more likely, I just don't know enough yet).

Thanks for the article. I didn't know about the EPPlus dll, so I learned something. which is the entire point of me being involved in this site...