OpenOrder with RadioButton

Hi,

does anyone know how to get the value from a pair of RadioButtons. I always get 'null'.

 

{
"Key": "radio1",
"Value" :{
"Type" : "Radio",
"RadioGroupId": "Group1",
"Label" : "radio1",
"IsChecked": "true",
"IsEnabled": true,
"Value": "radio1"
}
},
{
"Key": "radio2",
"Value" :{
"Type" : "Radio",
"RadioGroupId": "Group1",
"Label" : "radio2",
"IsChecked": "false",
"IsEnabled": true,
"Value": "radio2"
}
}

In my JSON there is always 

ContentObject: {".......","Group1":null,"UserComment":"test5"}

how can I get the value?

Cheers and thx for any advice

Tatjana