How to use the SCSIPeripheralsDriverKit.

We are creating an extension to send custom SCSI commands to a USB-connected mass storage device using a SCSIPeripheralsDriverKit. We specified IOUserSCSIPeripheralDeviceType00 as the IOProviderClass and set the device information in idVendor and idProduct. However, the dext is not being called even when the mass storage device is connected. Please help us understand what is needed to get the dext to work.