Sending parametrized raw body in POST Request

[TDLZocchio]

Hi, 

I'm facing a problem when trying to send a POST request via Call URL automation block. I want to parametrize the body using a Get Expression Value block. The value is retrieved correctly by the block but it doesn't get into the request body as seen in the images below.

How should I enter the block variable for it to get successfully substituted by its value in the body?

[TcnCunha_M]

Does this get expression doesn't have attributes?
Try to add into a input (variable) and use a variable 
Like this

[TDLZocchio]

Hi, TcnCunha_M, I tried to insert the value in a variable, but the problem persists.