Using entire select statement as Lexical Parameter in Oracle Reports 10g

I have created a lexical parameter x_sql whose datatype is character and initial value is dual in the user parameter section.

The sql statement is :- select * from (&x_sql)

Now the value of x_sql is fetched from a function in a package which is called in the Before Report trigger.

The problem is that I am not getting the required output.

The output which I got after running the concurrent program is:-

<?xml version="1.0" encoding="UTF-8" ?> 
- <!--  Generated by Oracle Reports version 10.1.2.3.0 
  --> 
- <INHOUSE_REJ>
- <LIST_G_DUMMY>
- <G_DUMMY>
  <DUMMY>X</DUMMY> 
  </G_DUMMY>
  </LIST_G_DUMMY>
  </INHOUSE_REJ>

Please help me and guide me.