[flexcoders] how to change vertical scroll position with variable row height in datagrid

[gur_sukh]

Hi,

I have a datagrid with variable row height( multiline rows). If the 
height of last row is bigger than the other rows, then only half of it 
is visible and half is below the visible area. 

I need to set the verticalScrollPosition so that the complete row is 
visible. My class inherits from DataGrid class. And the 
verticalscrollposition in datagrid is based on number of rows and not 
on piexels.

How do i set the complete last row fully visible, any ideas?

Jas