phone number format

Where can I find which format to use in contacts in order to have the contact information displayed instead only the phone number on the iphone.

I have bought a iphone in the Netherlands with a T-mobile iphone plan. The dutch numbers and contact information is correct displayed. The numbers from Belgiumare displayed with twice the country code and with no contact info.

settings: language: dutch; region notation dutch; keyboard dutch:
used mobile number format: +31 6 xxxxxxxx
fixed number format dutch: +31 xxx xxxxxx
fixed format belgium: +32 x xxx xxxx

Any clue where to check?

Regards
Iemke