Hi & welcome to HC
Have you tried the tissue method with your ham? If you put a tissue in your sleeve or somewhere it will get your scent then put it in the cage it will help your ham get used to your smell & realise it's not a threat, just repeat that every day for a while & that should help.
What's your cage access like? If it's from above it's a lot more threatening to a ham than from the front or side so you need to be really careful how you approach your ham.
Also it may be an idea to just try talking to your ham for a while so he get more used to your presence before you try to handle him, a week isn't long & some hams take longer to settle than others.
I wouldn't worry too much if you haven't got to wait long for a new wheel he should be OK for a short time.
Some hams do sleep in the open, I'd just be sure he has plenty of nesting material, preferably plain white unscented toilet tissue shredded up & let him make up his own mind where he wants to sleep.
Hope that helps a bit.