Zoom camera control over Herelink


i have a 30X zoom camera module, and I have a problem. The camera has 1 channel to control the zoom, so for example, 1100 is zoom out and 2000 is zoom in.

On the herelink the only one I can use for that is the wheel, but its already busy with the pitch gimbal control. If I use a button, I only can do the zoom in and if I relesae the button, it goes down to the min zoom.

so, seem to be I need 2 buttons to remote the zoom, but managing the same channel.

Any idea how to solve this? thanks!