HI!,
I found this in the doc:
https://docs.genesys.com/Documentation/Composer/8.1.4/Help/WebServiceCommonBlock, I understand that you are talking about what I need, what you mind?.
It makes sense that composer forces me to put a URL (literal) in parse/develop time but when deploy in other environment I should have the chance to change by the contents of a variable.
thank you very much.
Sergio.