(keitai-l) 3rd party mail servers for mail client in Euro i-mode phones

Hello, I am a consultant working for a client who would like to 
implement a corporate i-mode mail service using GSM based i-mode phones 
and their built in mail client (i-mail).

I have looked everywhere for information on the availability o 3rd part 
servers or support, but have found nothing.

The reference phone we’re working with is the NEC N400i which allows for 
2 custom connection settings, of which a portion of the settings we can 
enter are the following:

Mail server
2nd Mail server
Confirmation site
Username
Password

I found one good reference in this link:

http://www.appelsiini.net/keitai-l/archives/2001-11/0173.html

But discussion seemed to end on the use of an i-mode web page.

Are there any third part email servers that can be accessed using the 
built in i-mail client in i-mode phones? Preferably a server that runs 
under Linux or Windows.

I’ve pointed our test phone to our firewall changing the values for the 
above mail settings in the custom connection settings and have seen 
connection attempts to port 80 from the GSM/GPRS gateway when checking 
or trying to send mail.

Adding a 'Confirmation site' server address adds a 'Selective retrieval' 
  menu option in the Mail menu. When this option is selected, I'm taken 
to the web server hosted on the confirmation site server address.

I’m hoping that some one has or knows of a solution. Or possibly 
documentation on the exchange that takes place between the phone and server.

Thanks in advance!
Paul