how to update scrollabar offset in a flowlayoutpanel?

Hi to all,
i've a question for you.
i've a flowlayoutpanel without scrollbars.
when i push a button a panel will be added to the flowlayoutpanel.
This flowlayoutpanel has a fixed height and fixed width.
by using the flowlayoutpanel.autoscroll comand i want to fix the vertical scroll with an automatica routine.
For now the only one method i've found to update the vertical scroll limit is to set the flowlayout.autoscroll, first to true and then to false....
Is there another mode to update the vertical scroll limit without turning from true to false the flowlayout.autoscroll?

Thank in advance.