Hi guys, @reamon, @Holger_von_Thomsen @erossing.26610,
I managed to solve this problem yesterday in the morning.
All of you are +/- closer.
Let me explain this. After receiving the JSON PAYLOAD.
I’m using a built-in-service called: pub.json:jsonStreamToDocument to convert it. Official Documentation
So, what it does ?: It Converts content from the JSON content stream to a document (an IData object). This
service loads the whole JSON data into memory and then converts to an IData object.
In this case, we are talking about an array of objects, but when seeing the variable ate run time it is shown like this.

And everyone here in the office was thinking that it was a based64 string. But a based64 Variable has this format MTIzNA==, as it was mentioned by Evelyn.
Then I realized that this must be an Object Variable and I used another built-in-service called
pub.string:objectToString and while looping the data I mapped the object to a String Variable.

Final Result:

Thank’s to you all for the support.
I hope this topic can help more people in the future.
#webMethods#Integration-Server-and-ESB