I don’t have any experience with dlna personally, I thought some models had dlna support but could be mis remembering. If so there may be an easier way to do what you want.
What you want to do should be possible but may require tweaking a few things.
Coincidentally, I’ve been working on updating the tool historically used for shell access on these devices to work better with more models including yours. The updated file can be found here:
https://github.com/1000001101000/acp-commanderTo get a root shell via telnet:
java -jar acp_commander.jar -t <ip address> -pw <admin password> -o
You can then create your symlinks as desired.
They might now work at first since samba typically doesn’t follow symlinks by default. If so the following may need to be added to smb.conf or passed as a parameter when starting samba:
follow symlinks = yes
These devices generate their smb.conf dynamically when samba is started. When I’ve done similar things in the past I added the desired option $SMBDOPTIONS in the startup script. Check out /etc/init.d/smb.h