Hi,
To summarize the problem i faced , by default version of google javascript was fixed in previous versions to v3 now with the latest ones version is not specified so google uses the latest experimental version.
So far it seems that the current experimental version as a bug and doesn't works with IPad/IPhone and Android devices to move map with one finger.
Latest version 3.5 works.
So if you want to use a specific or latest known version you have to modify the GoogleMapsAPIUrl by adding the version you want
ex:
http://maps.google.com/maps/api/js?language=en&v=3.5Thanks to Alexander for his explanations