is the plugin providing an icon via making the GetIcon() method available in the plugin or populating it via the DeviceIcon64 field in the device properties structure. On first glance it does not look like the DeviceIcon64 is being read so i will fix that. You should change the actual bitmap size to 96x96 for good quality on the new device synch dialog
edit:
its fixed for the next update. You still might want to increase the size for a future release