Adopting Step Daughter

I was wondering if anyone has gone through the process of adopting a step child in Thailand. I am American and my wife is Thai. We have 1 child together and she also has a 5 year old daughter from a prior marriage. We would like to start the process to legally adopt. Not really in a huge hurry but would like to know the steps and if I would need to get legal help or if it is something that can be done alone. The Thai father is not around and said he has no objection to the adoption. We plan on living in Udon but think it would be best for the legal adoption for many reasons. If anyone has any suggestions or experience I would love to hear. Thanks in Advance.

There was a couple of threads related to adoption a while back, here's a couple of links which may help you out:

http://www.udonmap.com/udonthaniforum/v ... .php?t=285

http://www.udonmap.com/udonthaniforum/v ... .php?t=263