Horn connection for aftermarket steering wheel

i've searched but still confused.

i fitted a momo millenium 2 weeks ago. I have the wire for the horn, it's a yellow wire which I cut from the cruise/hicas/horn connector. if touch it to the body the horn sounds so that's straightforward enough. I'm not bothered with the cruise control so i've tucked the plug under the steering wheel.

I got a hub kit which fits nicely onto the column, it was sold separately but by the same supplier rockshore.co.uk(something like that) so everything fits correctly. What I can't figure out is how to get the yellow wire through the hub onto the horn switch on the new wheel. There is a black (presumably earth) inside the hub, but there is no hole or access to feed the yellow one through. is there some other spring/connector that should go between the hub and steering column?