Thank you, marcodagama!
There is a lot of techniques to make Search Engines "read" the markup schema, but probably there isn't a "one-size-fits-all" approach for your issue; in fact, you can make use of the following techniques together to make your content "readable". I'd suggest you to implement: (a) GEO Meta Tags (Geographic registration of HTML documents), although not all engines will follow it; (b) an Address property (address - Schema.org Property); and (c) data microformat within the HTML pages (Geo Extension Straw-Man Proposal), that some Engines may collect when crawling your client's webpage.