Call .Net assembly from a Biztalk Orchestration

I got a external .net assembly including app.config which I need to call from a Biztalk Orchestration.

I've put some logging into the .net assembly and can see that it doesn't read or can't find the app.config file as ConfigurationManager.AppSettings.Count is 0

I installed the .net assembly to the GAC using the gacutil /i path.to.dll and i'm not sure what happens to the app.config.

Any ideas on how I make sure the app.config is being read when I call it from a Biztalk Orchestration ?

Thanks.

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