Have done no more actual work on the topic but just a bit more thinking.
Part of what I teach here comes under the heading of "career preparation" - focussing on skills in English which will be useful when our Business and IT and Engineering students get jobs. The kinds of tasks we ask students to do include job applications, CV writing, etc.
For example an assignment was to find an advert for a job you really could do and write a letter of application for it. But naturally most of the jobs the students look for are advertised online and don't even give a land address - it would be odd to reply to an online ad with a letter unless it was specified.
Students tend to use email principally as a private-life means of communication, which means that they are not usually familiar with the norms of business-style email communication... sign offs like "I miss U" etc abound.
So it needs some thought and a bit of work...