@Reiner ********

better to transfer from outside. If you bring it in cash u should declared it on costumers when u arrive. They will give u a receipt.

Best you do first step and ask your IO office as Tod said.

I have same case.

For 60 days my IO in koh Samui said they ok with my old copy from translated married certificate and with the originally thai birth certificate from the half thai child. For 1 year extention they want the original marriage certificate, translated and stamped by my embassy in bangkok. Hope that helps.