Need help for cobertura report generation

[shamali hemke]

Hello,
We are trying to integrate cobertura into our application.
I am able to instrument the jar file. For this I had externally written one build.xml where I had written code for instrumenting the jar , so it had created the cobertura.ser file in current directory .
If I generate the report it is showing 0% code coverage as I yet to run the cactus test case.
Then I package the jar into ear & war and deployed it on Websphere process server .I manually ran the cactus test on instrumented jar through WID editor.I am using Websphere process server 6.2. but its not creating new cobertura.ser file anywhere WPS. If at runtime while running the cactus test I give the current location of my .ser file in VM arguments like -Dnet.sourceforge.cobertura.datafile=D:/cobertura-1.9/aa/cobertura.ser
it is not updating this .ser file.
Can anybody please point me out how to update existing cobertura.ser file if I run cactus test on instrumented code manually not through build script .
Can you please point me to right direction ?
Thanks in Advance. Any help is much appreciated.

Thanks
Shamli