I use NLog with next configuration:
Targets can be wrapped multiple times (in my case I had a filter), so the following snippet is a more generic approach to unwrapping that works for multiple levels and doesn't make assumptions about target names.
Target target = LogManager.Configuration.FindTargetByName(targetName);
while ((target != null) && (target is WrapperTargetBase))
{
target = (target as WrapperTargetBase).WrappedTarget;
}