I have had a quick look at the WetBox, and it would appear it was designed specifically for the cartomiser, and adapting it would eliminate the autofeed system it has.
However, as I dont own one, I would advise you to ask the question from the Supplier you purchased it from.
Also, read
through the review
thread on the
WetBox and if no one discusses your particular problem, I would suggest posting the question regarding getting the juice flow to the carto right.
Getting used to a autofeed system is never easy Keesie, so I am certain some other people will have had the same problems you are experiencing.