This is JCL's answer:
"Can we use plugins? - Yes, but only when including the source". The problem with 3rd party dlls is that they can include all sorts of resources. While I know that you are a serious engine user, some might hide resources in their dlls.
Send your project (including the source code for your dll) and the fmod dll. I will then download the dll from fmod.org and overwrite the fmod dll that comes with your project. This way, everyone will be sure that there isn't anything hidden inside it.