Soap problem with loading web services in libraries uipath

Hello ,
I need your help,
I need to make a SOAP call on UIPATH and for this reason I read this, I followed all the steps but I have some problems. After inserting the WSDL like the guide, all the services appeared in the UIPATH activities, but when I try to use the Login activity I have the following error. (The variables here are fake but I usually write real values). Here are three tests.

First of all in the activity Login I create two variables, request and response( view proprieties on the right). I use request to call the input of Login for insert company, pw and other, but when I run the code, it gives me the following error “ Multiple Assign: Can’t assign ‘company’ to request.aziendaName ”.
Request and response variables are LoginRequest type and LoginResponse type, as you can see in the picture.

And the variables with request., like request.aziendaName, are a string type.
I created the variables with the values and I insert the variables in the multiple assign activity but I have same error.

I don’t use Multiple Assign activity but single assign activity and the error changes,“ Assign Cannot create an L-value from the given expression with property ‘aziendaName’ because the target object is null. ” .

I have used the HTTP Request and it works but I would like to make this activity.
Do you have any suggestions on how to obtain a response using this activity?

Thank you.