Hello Everyone
After an email discussion with HereLink people, it looks like it is not possible to redirect the telemetry (Mavlink) to a specific IP/Port (considering UDP here). This makes the HereLink not usable when it is not the AP (wifi Access Point). In our case, we have a dedicated AP, so HereLink has not been integrarting in our setup well so far.
Never the less, as confirmed by HereLink people, it should not be a hard task and is more a matter of exposing the config, and giving a priority to that task
The original discussion is here : Herelink forward mavlink when NOT setup as Access Point
Plus, several emails with Alvin Lai :
“Connecting Herelink to a local network with Herelink not being the access point should be possible […]”
““Should be possible” means that under the existing hardware of Herelink, sharing mavlink data via local network is possible to do. However, we currently do not have the feature nor any plan to implement it.”
“By “look it by yourself” mean that if you want this feature, you will need to modify the codes on Herelink by yourself.”
Note that I have not received any code neither I have been proposed to get access to the code for modifying it. So I don’t know is modifying the code really is an option
Finally, Alvin Lai mentioned that this feature is not scheduled yet, and may be done faster if interest is shown about it :
“[…] its not supported in current version of firmware. The feature will added in the future versions.”
“I am afraid that there is no exact schedule on this. You may keep expressing your desire on the forum to have this feature putting on higher priority on our developers’ to-do-list. Gathering more people to discuss on the topic on Cubepilot will also help”
Here we are 
If you find yourself interested in having the feature of “Adding UDP IP/Port redirection of mavlink”, please do write about it. Don’t hesitate either to precise/expand what you think is useful, or describe your setup specificity