Just set all the numbers for his contacts to have the country code with a
+ before it, but leave off any access numbers, such as the 0. So for Hong
Kong store the number as +852 and then the rest of the number, for the
UK store as +44 and then the rest of the number. The network will know
that this is an international because of the +. This will then work in
whatever country you are in.
Hope this helps.