Tourist visa requirements for a Thai child under 11 years old travelling to china.

My Thai partner lives with me here in China. She wants to take her 10 year old Thai daughter on a holiday to China for 29 days. My partner has seperated from her previous husband fr many years and is the legal custodian of the child. The father has no contact with the daughter. Do we need any additional document apart from the Form V.2011A? The child has a passport and a Thai ID card. I will write a letter to financially support the child whilst living with us in China.