Warning : This seems not to work on created (transmuted) veins.
You can set the location, but it will not teleport you. This is being tested to verify the situation.
Upon a few test on Wurm Unlimited this seems to be true in the 15 test I did.
Can set it on a "natural" vein and teleport correctly.
Created (transmuted) veins don`t work even when the server was restarted after transmutation but before setting the vein.