Hi Mufeed
Ok so for your task your choices are:
1. Configure a decision key for each action you want to take. Implement the action itself in /IWWRK/BADI_WF_BEFORE_UPD_IB. You need to find/create a background function module or BAPI that applies the approval, rejection or whatever to the object of your workflow task.
2. Use the Open Task button with SWFVISU and intent navigation to launch to the same dialog you normally use in your workflow. This must be web-accessible. See note 2274940 - URL generation for intent-based navigation for more info
3. Use the extensibility option for My Inbox to do your own thing - you might need this if they have to enter some additional information (more than just comments or attachments)
Rgds,
Jocelyn