Scroll bars for a table in a popup

Hiya,

I have a looong table (around 50 columns) that appears in a popup.

If the user wants to scroll up/down they need to scroll across to the end of the popup before they can access the scroll bar for the table.

Maybe this screen shot will explain what I mean:

It would be nice if they could scroll up and down without having to scroll across the popup.

Does anyone know how I could have scroll up/down for table that wouldn't go off the screen?

Thanks!