Ah sorry that's my mistake, I thought it simply used the original didn't realise it used a custom skin.
In that case it doesn't appear as if the Author is still on the Hive as I don't see a link to their account. Therefore your best bet is to edit the skin as you desire and use it however if you seek to post it to contact the staff and let them know you've tried to get in touch with the original creator
The moderators are quite fair and as long as you've done your best to try and get permission they'll accept that, however like I said, best to let them know. Of course if your skin edit is for personal use then you don't need permission since no one will know if you've edited or not.