I'm not sure I fully understand your process. You send your work object to a wait shape in your flow and then are waiting for the user to open it up from a workbasket? Why aren't you just using an assignment? I feel like I must be missing something. Can you put up a screen shot or two of your flow? That might help bring clarity.
>>> But Button "Stop Waiting and Continue Process" is not displaying on screen
If this is a button you feel should be displaying on the screen and is not, then peek at the section rule on which this button is defined and see what condition rule is controlling the button's visibility (or if appropriate, look at what condition rule controls that entire section rule's visibility). /Eric