Getting number of days between two dates using DateTime.pm

[Loo, Peter # PHX]

Hi,
 
I am trying to obtain number of days difference between two dates.  Is
it possible to do this using DateTime.pm?  For example:
 
2006-09-06 - 2006-08-12 = 25 days
 
The result that I want is 25 days.  I tried using the 
 
$diff = $dur->in_units( 'days' );
 
but I am only getting the difference between 12 and 6.  The difference
between the months is left out.
 
Thanks.
 
Peter