Make him wear one of the "electric shock" dog collars when at work.
http://www.ebay.co.uk/bhp/electric-dog-collar
Tell him it is remotely operated by email, and if you dont get an email every 30 mins he will get a shock

Seriously, he is working to a different cultural standard. "Soon Come" has a sense of urgency just after "Manana"
Perhaps a small bribe might help? $1 per email whilst "on the job"?