Address book: fields automatically filled when sending mails?

In my address book i have all the info's in the name field...

es:
name: "John Smith"
surname : empty

But everytime i send an email to this Jhon Smith, i get the address book updated:
name: "john Smith"
surname: "Smith"

I know I can simply put name and surname separately, but i sync different phone and not all of them permits me to choose which info display first. So this is the only solution i find..

so..There's a way to block this unrequested autofilling?