Add logging to custom dll

We have developed a custom DLL to handle a few things that WFG does not (like sending an email FROM a specific user, for example). This DLL, once deployed to the wfg IIS directory is working as expected except for logging.

The dll uses NLog to write to a log file of a specified name and directory. This logging tool is common in our development environment (we use it in almost all of our custom applications, web apis, ecf, etc…).

I just can’t seem to get logging to work from this custom dll. Here is some configuration:

But, the log file is never created.
Any ideas?
Has anyone used nlog in a dll in wfg?