Hi Mihir,
With the same curiosity I tried to analyze this. Even if it is late, I will try to explain what I have understood.
There are two ways for approval
- If you are using UWL
- If you are using Module Specific Approval Components – Can say FPM or POWL
If you are using UWL, the above method (WI_EXECUTION_VIA_R3_INBOX) will be useful. The Task will be configured in SWF_VISU T.Code. So, in UWL the configured application will be executed. And at the same time the task should not executable in R/3. That’s y simply the error message was given if we are executing from SBWP.
If you are using Module Specific Approval Web Dynpro components (e.g.: E-Separation) the approval process basically will happen based on statuses. You can observe this in standard class CL_EAIN_OVERVIEW. The Workflow will be updated parallel if we approve from here (Can check in CL_EAIN_WORKFLOW).
So the Idea is, if the customer wants to approve from UWL and wanted different approach or more information than standard provided we can create custom Web Dynpro and can configure in UWL.
Experts, please correct me if I am wrong.