finding multiple keystrokes

[Stephen Kramer]

the following will select, in a list field, only the first item that  
starts with the first pressed key:

on keydown key
	find  normal key in  field "list"
end keydown

but if field 'list' contains:

abc
agh
aty

how can I make it so that the third line will be selected if the user  
presses "at"?

Thanks,

Steve