Confused with Island Storehouse

Im lev 50, I have placed an island storehouse on the first sector of new islands so i could place 3 generals there to fight the 1st sector. I have cleared 1st sector and i now have 2 sectors with nothing in them and a 3rd my explorers uncovered with bandits in.
My confusement is over other people reporting to be able to place island storehouses on main island and something else. I cant place any new island storehouses anywhere on my entire map and I have 37 build licenses left. I cant even place a storehouse on the sector i just cleared, is this normal? I cant place one on the small island that had no bandits to start with, is this normal?
whats wrong with it, theres no mention of having a limit on island storhouses or is there a level requirement to placing them?? thanks

Have you used another deed on the sector you just conquered?
You need to kill bandits - get deed from merchant for 8500 stalks - use it on sector you conquered - then build the storehouse.