the easiest way to turn it off, ( for pro rate advantage ) is to call Customer Service.
is your hotmail attached to your home ISP provider cable or dsl
likely it will not let you send from a differnent ISP connection
if this was free sign up account not comming with your landline ISP, then it is a matter of correct settings on the PC,
IF your using the same PC and the same account settings, but it won't work with the vzw connection, you will need to use the web access to your hotmail acct NOT outlook, or setup a different acct and use the hotmail address for the 'REPLY TO' for anyone responding.
in others words an indirect or redirect labling
other users with more hotmail and out look experinece can help you with this