first, USER_SOURCE is a view.
and u cannot add entries to oracle dictionary.
why dont you just create a stored procedure, 
using dynamic sql? something like this?
and now, u can call this procedure CR_PROC which creates a procedure.
SQL> ed
Wrote file afiedt.buf

  1  create or replace procedure cr_proc
  2  as
  3  begin
  4  execute immediate ('create or replace procedure test23234 as begin dbms_output.put_line(''test'');
  5* end;
SQL> /

Procedure created.

SQL> exec cr_proc;

PL/SQL procedure successfully completed.
SQL> set serveroutput on
SQL> exec test23234;
test

PL/SQL procedure successfully completed.

SQL>