Hi Kumarpal,
According to my understanding manager approves OT in IT2002 , instead if you use IT2007 you can follow below link and check for the feasibility .
Please check this link : http://scn.sap.com/thread/3699009
Here in the link there is document created by Vivek , which is an wonderful document for OT approval using IT2007 .
Please correct my understanding if I am wrong , do let me know.
With Regards
Aditya.T.M