newby question for libesmtp & sendmail

[brokkolo <brokkolo operamail com>]

i work on a home machine (dialup) with sendmail,
if i don't compile libesmtp support i can send mail throwgh sendmail without having it running (not sure of the tec term but sendmail fires up when i send mail...).
compiling libesmtp support (an wanting to use my sendmail and not relay on isp mta) i need to have sendmail running as deamon... so he is listening on port 25... (localhost:25) 

is it possible to use libesmtp for isp mta, and then change to local sendmail but not having it to be listening and running on port 25? can libesmtp pass the mail to sendmail the way balsa does when not compiled with esmtp support?
(what is the main difference with having sendmail befave the first way or as deamon?)

thanx
brook