Your JSON is missing the last "}", or is that just a typo in your post.
What version of of AwareIM are you using?
I got this working (sort of) using build 2711.
I say sort of because only 1 BO_Child was created and the fieldname was populated with
value1value2
I do not guarantee that I did not do something wrong myself, but I don't think that is what you want.
My guess is that AwareIM can not handle arrays in the format of
["value1","value2"]
I am no JSON expert, but I have only seen arrays like the following (which creates 2 BO_Child objects as expected)
{
"data": [
{
"fieldname": "value1"
},
{
"fieldname": "value2"
}
]
}