I'm not sure exactly what you're asking. You have a Kenwood H/U and a seperate Kenwood preamp or is that part of the H/U? Your Kenwood's outputs are at preamp levels so you don't really need an additional preamp. As far as the x-over goes, it depends a little on what you're planning on doing with it.
The x-over should have a main input (RCA) and 3 outputs (tweets, mids & subs). You should be able to run a RCA patch cord (get good shielded kind like Monster Cable's XLN) from your Kenwood's rear output ( If there is more then one set of RCA's generally the rear spkr outputs are used, not sub or fronts) to the input of your x-over. From there you can run additional patch cords from your various outputs to your amp(s). Fairly simple, but I'm not sure that's what you're asking. Does this answer your question? If not then elaborate a little on what you're after. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif