FindPath on static water

[Zik]

We replaced water landtiles with static water, and made a seabed.
Water tiles are arttiles with flags: impassable & wet.
Now we have a problem with sea creatures, because FindPath returns "Failed to find a path." error.

But RunAwayFrom function works great, and mobs can move on water(in my AIscript runlikehell function ). How does it's pathfinder differ from FindPath's?

Is it possible to fix it coreside?
And is it possible and efficient to make my own FindPath? For example based on Lee method(wave-search).
Where can i see sourcecode of RunAwayFrom and FindPath? is it written in eScript?

Thanks in advance for any help!