DOMINO MAIL ACCESS from  outside company

Your question falls into 3 parts :
- redirection to the mailfiles from your reverse proxy
- connect every authenticated user to his/her mailfile
- Single Sign on between Websphere and Domino

What you do, is create a "rule" to point everything that looks like

http(s)://edgeserver/mail/*.nsf

to your Domino server.

You can further refine this (I think in Websphere Edge too) by creating a regular expression rule

eg. if your mailfiles all have 6 characters, all uppercase, you can have this (I'm not very good with reg expressions, so change where needed :-) )

https://edgeserver/mail/[A-Z][A-Z][A-Z][A-Z][A-Z][A-Z].nsf

You could create a separate rule per mailfile, but that's probably too much work and not really worth the hassle.

Now to have every user connect to his mailfile, you can use the redirect database that comes with Domino 7 (create a new database from template Domino Web Access Redirection database, see the help for details).
Create a rule in your reverse proxy too, to access this database (for instance http://edge/accessmymail -> (your domino server)/redirect.nsf)

Single Sign on between your Edge server and your Domino server, is done by importing the ltpa token from the websphere server into your Domino directory.  You probably already have the same authentication source ? (you use Domino as authenication directory in your Websphere server ?)

cheers,

Tom