The Kawasaki accessory case is a MonoLock case, so it has a different platform base than the slightly larger, more spacious MonoKey cases. Thus, any Givi MonoLock cases will fit.
If you decide you want to go with a MonoKey case like an E360, you'll just need to spend about $39 somewhere like Twisted Throttle (I would recommend the SW-Motech base over the Givi base it is more durable and cheaper than the Givi base) to get a MonoKey base, then you will be set to mount a MonoKey case on your rear rack.
BTW, I am speaking from experience - my bike came with the Kawi accessory case, but it wasn't suitable for my interests - so I switched.
Last edited by ednukey; 07-05-2009 at 01:55 AM.