Setting Environment for Oracle XA - dbms_system

Hello,
  
  I habe some questions concerning the Documentation
  http://e-docs.bea.com/wls/docs81/jta/thirdpartytx.html
  
  and the Section "Set the Environment for the Oracle Thin/XA
Driver".
  
  The problematic sentense is:

[i]  (when using the Oracle Thin driver 10.1.0.3 or later) 
  grant execute on dbms_system to <user>;[/i] 
  
  The database team colleagues claim that this requirement could be a security
problem.
  The documentation of this package has been left undocumented or
  removed from the official Oracle documentation in some later release.
  
  Though, there are some scare references to this package I have not found the
definition
  http://www.oracle.com/pls/db102/master_index?letter=d here as well.
  
  What is your opinion to this topic?
  
 
  Another point is that it seems that this package is not accessible directly
and
  must be installed in a separate step. The should be some script prvtutil.plb,
which creates
  the package. Am I right? 
  (I know it is an Oracle not WLS topic, but maybe you have done it already)
    
  I'll be glad for any comments or background information.
  
  
Best regards
Jaro

WLS 8.1. SP4