I have a simple need with Quality Center 10
If you noticed in Quality Center Client on IE 8 -> Test Plan. If you create a new Testcase with Test Type = 'VAPI-XP-TEST', it will ask you for Script Language and Script Name. I have selected Script Language to be Python. Once you have gone through this process of creating a new testcase, the testcase is pre-populated with a Default Python Script.
I wish to know how I can modify that Base Default Python Script so that the future new testcases will have my default Python Script? Is there any way to do the same through OTA API?
Thanks,
Amit
Can you post the default script here ? Iam not sure why you cant edit it ? You can edit the script as you want. 
There are 2 ways you can run the QC script one using VAPI-XP-TEST as you are doing , in that case you can use tdhelper object for updating the results.
Second is OTA-API which you  can use python script externally to connect to QC and execute your tests and also update run results. there is lot of documentation available on QC help for OTA-API
Quality Center VAPI-XP-TEST - Modify Default Python Script