If I understand correctly, you want to have your iNotes client set to a webmail account, like you would with Thunderbird or Outlook.
It doesn't work that way, though. Your iNotes is to allow you to check on your Notes mailbox via a web browser. You cannot link it to an exterior account.
What you can do for getting webmail is set your webmail account to forward mails to your Notes address (by using your Internet Address that is in your Person document in the company Names database).
I've got nothing to hide, and I demand that you justify what right you have to ask.