I am not very familar with crystal yet, though I did work to customize something called eportfolio, I am a web designer so I had a go at it!
What I did there was customize all the css pages to display the way the organization wanted it!
It should be fairy easy!
If I remember right there was a page called settings.csp which displayed the users preferences, where the user could select his/her choice
is this what you mean by the parameter page ?