SAP Workflow with Persistent class?

     Hi All,

     I am new to SAP Business workflow and am trying to create a small approval process flow.

     In workflow task, I am using ABAP Class instead of BOR object.

     Since IF_WORKFLOW has persistent interface, can we still use persistent class with workflow? Could anyone post any example?

     I found one example Using persistent objects in SAP workflows

     But, it is little confusing as there are 2 classes ZCL_PERSISTENT and ZCL_WORKFLOW and no link is mentioned between the 2.

     Any help would be of great use.

     Thanks,

     amruta