Refreshing DirectoryIndexExcludePolicy

I’m using DirectoryIndexExcludePolicy to mark directories that are typically excluded for my language. This works fine, except for directories which are created by the build process during project creation - in brand new projects, these are not correctly marked, but after a subsequent refresh, they are. Is there some way I can manually provoke a refresh after project creation? I tried SaveAndSyncHandler.scheduleRefresh(), on the theory that the directory might have been created on disk but not reflected in the VFS at the point that that extension is polled, but that didn’t help.