Sirius connection help

My old Kenwood head unit finally bit the dust, so I bought a new Kenwood unit to replace it. I bought the KMR-355U head unit. I already have the Sirius SIR-KEN1 satellite radio tuner. The problem is that the cable on the SIR-KEN1 is too big to plug into my new KMR-355U. I've been looking for an adapter or a new cable I need to buy but have only found tuners. Do I have to buy a new tuner to connect to my head unit? Any help here is great...