IIS WAF scaper does not traverse sub folders

[FuhuXia]

With a WAF folder structured like this:

$ tree
.
├── one.xml
└── mydir
    └── two.xml

On IIS server it display like this:

Tuesday, June 30, 2015  3:41 PM        <dir> mydir
Tuesday, June 30, 2015  3:30 PM        13867 one.xml

WAF harvester only harvest one.xml. It does not go into mydir.