Changing Character Set in Visual Studio

A plugin I’m writing uses a .h and .lib from an external library. Unfortunately the plugin crashes the editor if I use Unicode character set. I know this is true by creating another console application in visual studio and toggling between Unicode and Multi-Byte under Properties->General->ProjectDefaults->Character Set. Though under my Unreal solution, I don’t have this setting under my properties. Would anyone know how to fix this, or how to set the character set to multibyte in unreal? Attached is a screenshot comparing the properties.

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