Get the coordinates of siege engines

[hylomorph]

Does anyone know if you can get the world position of a siege engine (ballista, etc) placed by the player?

I know the following does not work:

With the reticle over the siege engine, the following only returns (0, 0, 0):

GetUnitRawWorldPosition("reticleover")

While interacting with the siege engine, this also returns (0, 0, 0):

GetUnitWorldPosition("interact")