USE THIS FIRMWARE AT YOUR OWN RISK!
Firmware for the WL-HMD can be found using this url:

http://website.wl500g.info/beta/firmware.php?fid=49

Changelog:
WL-HMD English Firmware Version, version 1.2.3.9
Installation Notes:
1. Upgrade the device with the firmware 1.2.3.9. : WLHMD_1.2.3.9_en.trx
2. Reformat the hard disk drive with the “Disk Tools” (The Web Manager’s page in the section “Storage Setting”) (note: it will lose your data in the disk, please copy the file to another disk before format)
3. Copy the media file (media.tar) to part1 (1st partition created on the disk at step 2)
4. Click “Restore” in the Factory Default" (The Web Manager’s page in the section “System Setting”)
5. Put some files in "part1/media_server" on the WL-HDD (Using ftp or the Web Manager’s “Disk Share”)
6. Start the Dixim Media Client.

In “C:\Program Files\DigiOn\DiXiM Media Client”, you may have to modify the “DmClient.ini” file according to your WL-HMD’s IP. But in my case, it’s working without this reconfiguration while connecting to the Media Server through wifi…
Example:

[StaticMediaServer]
Entry=2
1=http://127.0.0.1:30000/
2=http://192.168.0.100:30000/