So.. After you've run the scan, you've found yet another false positive in Nessus due to the idiosyncracies of your environment. Here is a script to purge a particular plugin from a Nessus report so you don't have to redo the scan after fixing your scan parameters.
This may work on OpenVAS reports, let me know if it causes a problem. As always, improvements are welcome.
Updated: pauldotcom from Twitter makes an excellent point that this can be achieved using the "Report Filters" interface. I blame my fear of flash guis for not finding this.