Why is "Do you want to give him a promotion" not good?
I think it the correct translation as well.
The subject of the Danish sentence is the first-person "jeg", while in your answer the subject is the second person, so they do not really have the same meaning at all.
You're right. :-)
I was certainly mistaken by "Skal vi ikke lave en snemand" which is translated as "Do you want to make a snowman". :-D
It is literally "Shan't we make a snowman" ;)