The latest geoqlik version allows you to display information on a map from longitude/latitude or from postal addresses included in your qlikview document. Geocoding is done with openstreet map data or with google if you provide your google key. Greek characters in addresses are not a problem since GeoQlik supports unicode.
Unfortunately the trial version of geoqlik does not provide the address geocoding but I suggest you to contact business geografic to ask them for a demo with your own data.
With a bit of effort you can get the longitude and lattitude from Google as well.
I did the following:
(1) Create a table with all your customer addresses (in my example the table Addresses)
(2) Have on field with the full address as required by the Google API [Street,+ZIP,+Town,+Country]
(3) Loop through all these addresses using the following script:
for i=0 to $(noRows)
let b = peek('FullAddress',$(i),'Addresses');
'$(b)' as FullAddress,
([result/geometry/location/lat]) as Latitude,
([result/geometry/location/lng]) as Longitude
FROM [http://maps.googleapis.com/maps/api/geocode/xml?address=$(b)&sensor=false] (XmlSimple, Table is [GeocodeResponse]);
I have added a sleep statement to the loop in order not to bomb Google.
Once you have all the Longitude / Latitude information I think you can fulfill your requirements with the standard Google Maps solution, or, alternatively with some of the free extensions posted here on the forum: