Milestones through gates

[Interrogation]

I was planning to make harbor in a claimed lake to put my snekkjas and knarrs using the milestones.

It already had the signposts for it but i had to cover the lake with palisades for my buildings. Through common sense i thought signposts couldnt pass a palisade wall so i made a normal gate for it, since the visitor gate may cause some trouble.
But i still couldnt travel using the signposts with the gates open, Wouldnt it make sense if it was possible?