What I would do is to create another Linux user account and configure Evolution in the second user account to use that second Exchange account. This isn't as inconvenient as it may seem. You can log in to the console under one user account, then open a terminal and su or sux to the second user account. I do this to keep my private files away from the account that I use to access the Internet.
The second account has to set the DISPLAY variable to :0.0 and then it can use Evolution or any other GUI application.
Code:
user1> sux - user2
password: ****
user2> evolution &
Make sure that you use the dash after the su or sux command.
This solution is a lot easier and faster than trying to work around a limit in Evolution.
The latest SuSE has sux as a link to su. It seems that the SuSE developers incorporated sux functionality into the su command. Gentoo has deliberately left the sux command out of its distribution because the Gentoo developers consider sux to be insecure.