if you are using jsf  so why not make most use of it? Why do you try to use old features of web!!!

instead of using request parameters, you had better to put  a field in your managed bean.
this RequestParameterMap is readonly structure.

consider you have a jsf managed bean as follow:

class MyBean {

    private String myKey;

    //somewhere in your code: myKey = "myValue"

    public String getMyKey(){
           return myKey; 
    }
}