well i have to do the same layout design for many web pages.
then i have an area of 500 * 350 that changes with the pages.

my idea was to do design a user control that contains this area, the do
something like this:

<uc1:panel>
 here i design the page, and include any html or asp tags  
</uc1:panel>

I tried this by putting in the usercontrol a div tag with overflow=auto
and fixed its dimensions , put it didn't workout.