for DTV its just documents what you need tô preapare, before you go and admit them outside country.. all tuhose documents you can get from thailand . Just need to give passport.. from your side … thats all …
After that its 99% that you will get your visa from Vietnam embassy or Cambodian .. or others …
I know agent and people who have done it .. if its not changed last 3-4 months .. then i am not wrong.. and its a small thing what can do thailand if you have money.. i cant post the things here what ive seen on my 7 years what ive spent here …