Start feeding the dog in the crate. This is the quickest way to get the dog to love the crate. Only give treats and goodies while going into the crate.
Have you tried sliced chicken weiners or small pieces of cooked chicken or roast beef as treats? Most dogs cannot resist.
I agree with the other's....start by leaving in the crate for very short times while you are at home. Make the dog understand that even if you are home he can be in the crate.
You might try moving the crate into the living or family room or kitchen. Somewhere where there is more action.
More exercise is also a good idea. Get him so tired before you leave him, he has no time to fuss...he will just want to sleep.
Get in touch with the rescue, they should be able to help you with ideas.
Since this rescue dog has been in your home such a short time...you must realize that it's going to take some time for him to fit in and settle.
My rescue China drove me nuts for the first 3-4 months...she was glued to me...everytime I moved she was stepping on my heels.
You just have to get them to understand that you can leave them and that you will be back. Do the same rituals and say the say thing everytime you leave.
Gina