upgrading from WM5.3 to WM6.2

Hi Experts,

We are upgrading from Work manager 5.3 to Work manager 6.2 . While upgrading application I just created "Workorder" class by extending standard Workorder class. I did n't changed any functionality.After that in config panel replaced the standard class with customized class with standard class.

Added the customized the jar in "Java" folder after that added the jar path in Agentry.ini file.

But when we synch the application getting an error in ReadClientWorkorderStepHandler like

null object wo in method wo.setProperties

So if we replace the standard class with customized class in config panel,whether the parent class will available. If that is the case why I am getting this error.

Please suggest.

Regards

Vijay