I previously had the 6 qt bowl lift Kitchenaid mixer and used the ice-cream maker with it. I upgraded to the KSM899ODP. I can't seem to get the top part to sit tight to the motor, is there a part I can purchase to be able to use my ice cream maker with it?  I have been able to use all my other attachments as well as my 6 quart bowl, so I was hoping the ice cream maker would work as well......thanks for any assistance.