Using the D5000 and D3100 we have actually just taken it off entirely – if you pull on it slowly but firmly, it will come out – if you do so at an angle, it comes out undamaged, so you can always replace it if you want to. Some customers have chosen to cut a hole in it to keep the sealing effect. We do not have a replacement cover but might look into it in the future.
For the D7000 we did not come up with a satisfying solution yet. The rubber does not come off easily and we haven’t been able to test it properly. One of our customers solved the problem by cutting a whole into the rubber which still allows the Unleashed’09 to connect to the port.