Do you have a workbook example of what you are working on? Parameters don't make much being in the pages shelf - similar to a flip book or pages in an animation, the pages shelf work best when the field represents multiple values that a user can step through in sequence. Parameters, on the other hand, only represent a single value so there's not much of a selection of values to show.
It might be helpful illustrate how the user will interact with the parameter and how we expect the view to change. I'm not sure if pages shelf is exactly what you are after, but if you can show what you want to accomplish we might have some other ideas to use.
I've attached a very simple workbook. It's three columns - opportunity name, probability, and Last Modified Date. I created a parameter and calculated field that returns the difference of the two dates whenever the parameter value is greater than the last modified date. I wanted to represent this in an X-Y scatter plot with probability in the Y axis and days since last change in the X axis so I can see how long it's been since an opportunity has had activity as I slide along the reference date. The opportunity, when modified, automatically gets stamped with a new date, which shortens the trail.
However, I want to see a history trail as well that shows the opportunity at the last modified date as well, which I think means I would need to use pages, but I'm not sure. Any help is very much appreciated! Thanks!
Thanks Dani for the clarification. Unfortunately parameters don't have a concept of history, but you might be able to get close using multiple parameters and dual-axis to represent the shift from one parameter value to the next.
In the attached workbook, I duplicated the parameter and the days since calculation so that there is two version of that value. This helps represent two different state for the parameter value to be graphed against. Hope this helps.