WS-Directory does not include any metadata in each entry except entry-reference.  On the other hand, modification time 
of a directory is useful to know whether a client copy of entries is up-to-date or not.

For Grid file system, we would like to attach several metadata additionally in hierarchical namespace (directory 
structure), which includes times, size, checksum, and possibly ACL.  We would really like to have extensibility 
interface to add metadata..