forward path in sendmail.cf file

Hi,
 I am using procmail as my local mail delivery agent and I have the following
defined in my sendmail.cf file:

O ForwardPath=/etc/mail/vacation/.forward.$u:$z/.forward.$w:$z/.forward

But when I have a /etc/mail/vacation/forward.$u file for user $u, the local
mail when gets delivered, does not consult this file at all. Do I need to
specify any specific flag in my sendmail.cf file to this?

Please reply me at akumar(_at_)eng(_dot_)fore(_dot_)com

Thanks in advance for any help.

Regards,
Arun