Hi @ipoblete ,
Adding to what @Pro_Tanvee has mentioned in the earlier reply, what you want to do is pass the JSON body inside the HTTP Module’s Request Content instead of Query Parameters.
So, Something like this should do the trick,
And, JSON will look like this from your example code snippet,
{
"emisor": {
"tipodoc": "39",
"servicio": 3
},
"detalles": [{
"codigo": "10001",
"nombre": "Pan",
"cantidad": 1,
"precio": 500,
"exento": false
}],
"expects": "all"
}