pine and sendmail problems

[randy turner]

hi all,
my isp changed there mail system,
now i have to add my domain to my user name
from what i am reading pine uses the user name from the system,
well for  example i log in as rturner2
now that worked fine when my isp did not require me to
add on my domain name,
i just created a new user and that worked fine,
my isp wants my login for email to look like this
rturner at texasisp.com
because pine uses the $user and i can't create a new user
with the domain added on to my user name,
i don't know how to fix this problem.
any ideas on how i need to configure pine or sendmail to accept this?
thanks in advance
randy