AFAIK hiddenselectionstexture doesn't work on weapon attachments anyway, even if they are set up with selections inside the model.
Same goes for most proxy items.

Works on the weapons themselves though.

Ah. That's really unfortunate if it's true.

Hi, can we expect this to be fixed with the Marksman update (as it's already assigned)?

Can any information be provided on the status of this?

Camo selections for a couple of weapons have been added to Dev Branch earlier this week (TRGs, Rahim, and Zafir, I believe). I'll eventually adjust the rest, as well. Unfortunately, it won't be possible with attachments.

wait why it can't be done with attachments? please explain the issue

i know the attachments doesn't support hiddenselections feature ,but they really need that reskin feature because it makes things much easier

http://feedback.arma3.com/view.php?id=24113

Camo selections don't work with attachments, as was noted above. We are aware of the feature request concerning this, which you linked, but I have no ETA for that.

Thanks for the update! I appreciate it even if it's not all of them.