How can I use variables from LHS to modify an attribute in RHS using business rules editor GUI??

Also I added a new function trying to work around but didnt work....

I need to get this using business rules editor (GUI):

rule "my rule"
no-loop true
when
$f: Fact(number >= 10, $s: score)
then
$f.setScore($s + 5);
update($f);
end

Thanks.

                                                                        
Felipe Piccolini M.
felipe.piccolini@bluesoft.cl