Hi, sorry for a delayed reply and many thanks for your comments
if you ask my for the last name , because i would like she has my last name, and to prevent some trouble could appear when request the Argentina Nationality, Only this reason.
As per my girlfriend if she has a her family name . probably will be more easy include she in the mother's family book that with my family name and since I sincerely do not know the laws of Laos and since we are not married, it seemed to me in the first instance the most appropriate thing for us.
Actually the birth certificate already made for a ministry of home affairs in Xayaburi province, my concern in this moment i need this certificate attested for the MOFA Laos , and due we are not married, i don't know what problem will coming with this.
you mentioned businesses in vientiane that can handle this , do you know or could suggested one ?
Thanks and regards
Eduardo