Using log4net on nmodbus from not-main-project in a WPF project

Question

So, i'm taking over a old project that uses nmodbus (and old version at that, 2.0_1.11.0.0, we decided it was best to not update). Nmodbus uses log4net for logging messages. I need to be able to view the logged messages, but it seems like log4net doesnt like WPF, or being in not-main-project.

Adding

[assembly: log4net.Config.XmlConfigurator(ConfigFile = "log4net.config")]

To the Nmodbus project AssemplyInfo.cs file gives me this error:

Severity    Code    Description Project File    Line    Suppression State
Error       Unknown build error, 'Cannot resolve dependency to assembly 'log4net, Version=1.2.10.0, Culture=neutral, PublicKeyToken=1b44e1d426115821' because it has not been preloaded. When using the ReflectionOnly APIs, dependent assemblies must be pre-loaded or loaded on demand through the ReflectionOnlyAssemblyResolve event.'  OptimalProdTest     

Adding log4net, with NuGet Package Manager, to the main (WPF) project causes Nmodbus to stop working. (maybe has something to do with log4net being an older version in the old nmodbus project, and adding with NuGet will download the newest? Can i somehow add log4net from the other project into the main project without NuGet?)

I found other people with similiar problem who said i should add:

FileInfo configFileInfo = new FileInfo("log4net.config");
log4net.Config.XmlConfigurator.ConfigureAndWatch(configFileInfo);

to "the entry point of your library setup your logger", one guy said, another said "in the constructor of the wrapper class". However, i do not know what files these guys are talking about, nor do i know which project they meant (add to main project or nmodbus?). ( https://social.msdn.microsoft.com/Forums/vstudio/en-US/0c5d7fbb-94a3-4221-ab91-9732c5acee58/cannot-resolve-dependency-to-assembly-because-it-has-not-been-preloaded )

I'm lost and i can't find much help when googling. Anyone has any idea what i should do to be able to view the logs from log4net in nmodbus?