Oracle configuration required for XA Transactions

 Could someone please point me to an article or manual which details the settings (grants) required for Oracle to be used with XA Transactions in a J2EE environment. I have found numerous articals (via Google) but they are all not definitive (only theory from individuals).

Our stack is Websphere and Oracle 10.2.0.4.

In order for XA to work we require our end uses to run the following script as the SYS user:

GRANT SELECT ON pending_trans$ TO &BANKREC_USER;
GRANT SELECT ON dba_2pc_pending TO &BANKREC_USER;
GRANT SELECT ON dba_pending_transactions TO &BANKREC_USER;
GRANT EXECUTE ON dbms_system TO &BANKREC_USER;