need help with tiling issues

i am currently working on new kelp art:



now it looks all fine, but the only way to render it underwater is to use
TILE_ART_TYPE_HALF_TILING
in the feature artdefines xml. if any kind of other tiling is chosen the parts of the kelp that are below the water line, will not be rendered. my problem is that the kelp is not placed at the center of the tile, rather there are 4 kelp instances placed at each corner of the tile, making it difficult to see what tile has kelp on it.

Is there any easy way to fix this?

I am having exactly the same problem but with a land feature.

i did not find any quick way to fix this, so i had to make my feature tileable (i.e. creating 15 instances and make according to the tree tiling)

here is a screenshot of the final version: