Generating walls

[Rawzid]

I've just recently started playing on this server and I ran into a bit of a problem when trying to generate walls for my base. When I placed the water down to make it so it touched the lava and create cobblestone, it didn't work. The water seems to only spread in areas where there isn't lava. Breaking the block below the water doesn't cause it to go down when next to lava either. I'd appreciate some information or help. Thank you

 

[Depthstrider4]

use genbuckets from /shop under "raiding/ base items"