To use the Vaisala Humidity Calibrator HMK15 with the DMT132 you need the special cover set (Vaisala order code 230914). The cover set includes one salt jar cover where one of the holes is specially designed for the DMT132, and rubber plugs for covering the unused holes.
The hole for DMT132 is raised higher than the others, and has an ISO G 1/2" thread. The DMT132 can be mounted on the salt jar tightly using the thread, and without having to remove the filter.