BandiTT,
You can't use Twonky to gain access to your WL-HDD. Twonky runs as a server and you can get music/video/pictures from WL-HDD (streaming).
To read/write to your WL-HDD you can
- Use FTP
- Use Samba
Using FTP you connect using an FTP client (e.g. FileZilla) and then you can read/write/delete.
Using Samba. You must first install a custom firmware (Oleg's) and then you should be able to access the WL-HDD just like a "normal" HD. I have no experience with this, but there's enough info on this board.
Hope this helps!
Jeroen