wpf ,setup and deployment ,orca

Question

I am using VS 2010, setup and deployment project to create MSI. It is per user installtion.

I am having custom action to run <my prrocess> on commit. It is working fine on installation. I have to support Upgrade as well.

At the time of upgradation, I have to check for running process and if "My Process" is running I have to kill the process  and continue installation.

Added a custom action to kill the process by using the methods "OnBeforeInstall", "Install", "OnBeforeUninstall"  and "Uninstall" none of them are getting triggered and getting the Files in use dialog of Windows installer.

Using orca tool changed the custom action sequence to just before the InstallValidate in "InstallExecuteSequence". Still it is not working.
In the CustomAction section my custom action  Type is 51

Can any one help me to solve the problem.