Wow! It seems ridiculous they would make the controller with a jack that is not available anywhere. Could this be a type of cable that is readily used in Europe but not in the states maybe? I'll have to look at the controller and see if it opens up easy enough where a 3.5mm jack could be installed in place of the stock 3.45mm DC jack. Then a normal cable could be used. If they're using a DC barrel jack, I would assume there's only 2 wires needed. Before I do anything, I'll wait for your diy cable test.
The last thing I would recommend is swap the jack out on the pump. Making or adapting with a cable is going to be the best option. Funny thing is, I cannot see this type of plug being common anywhere in the world! LOL. More information to come soon. Give us about a week to get the parts ordered and build the cable.