I use Windows Active Directory as LDAP server and I modified SOGo Integrator to use the name of the Windows user instead of the user name of the mailaccount.

source code changes:
\chrome\content\sogo-integrator\sogo-config.js

else
sogoConfig['username'] = mgr.defaultAccount.incomingServer.realUsername;

replaced by:

else {
  var user = components.classes["@mozilla.org/userinfo;1"]
                .getService(Components.interfaces.nsIUserInfo);
  sogoConfig['username'] = user.username;
}

This is the GNUstep config:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//GNUstep//DTD plist 0.9//EN" "http://www.gnustep.org/plist-0_9.xml&quot;>
<plist version="0.9">
<dict>
<key>NSGlobalDomain</key>
<dict>
</dict>
<key>gdnc</key>
<dict>
</dict>
<key>sogod</key>
<dict>
<key>OCSEMailAlarmsFolderURL</key>
<string>postgresql://sogo:XXX@127.0.0.1:5432/sogo/sogo_alarms_folder</string>
<key>OCSFolderInfoURL</key>
<string>postgresql://sogo:XXX@127.0.0.1:5432/sogo/sogo_folder_info</string>
<key>OCSSessionsFolderURL</key>
<string>postgresql://sogo:XXX@127.0.0.1:5432/sogo/sogo_sessions_folder</string>
<key>SOGoACLsSendEMailNotifications</key>
<string>NO</string>
<key>SOGoAppointmentSendEMailNotifications</key>
<string>NO</string>
<key>SOGoEnableEMailAlarms</key>
<string>NO</string>
<key>SOGoFirstDayOfWeek</key>
<string>1</string>
<key>SOGoFirstWeekOfYear</key>
<string>First4DayWeek</string>
<key>SOGoFoldersSendEMailNotifications</key>
<string>NO</string>
<key>SOGoLanguage</key>
<string>German</string>
<key>SOGoMailDomain</key>
<string>XXX.XXX</string>
<key>SOGoMailingMechanism</key>
<string>smtp</string>
<key>SOGoProfileURL</key>
<string>postgresql://sogo:XXX@127.0.0.1:5432/sogo/sogo_user_profile</string>
<key>SOGoSMTPServer</key>
<string>XXX.XXX.XXX</string>
<key>SOGoSuperUsernames</key>
<array>
<string>XXX</string>
<string>XXX</string>
</array>
<key>SOGoTimeZone</key>
<string>Europe/Berlin</string>
<key>SOGoUserSources</key>
<array>
<dict>
<key>CNFieldName</key>
<string>cn</string>
<key>IDFieldName</key>
<string>cn</string>
<key>UIDFieldName</key>
<string>sAMAccountName</string>
<key>baseDN</key>
<string>dc=vision,dc=local</string>
<key>bindDN</key>
<string>cn=SOGo Administrator,cn=Users,dc=vision,dc=local</string>
<key>bindFields</key>
<array>
<string>sAMAccountName</string>
<string>mail</string>
</array>
<key>bindPassword</key>
<string>XXX</string>
<key>canAuthenticate</key>
<string>YES</string>
<key>displayName</key>
<string>Active Directory</string>
<key>filter</key>
<string>(objectClass=person)</string>
<key>hostname</key>
<string>192.168.XXX.XXX</string>
<key>id</key>
<string>directory</string>
<key>isAddressBook</key>
<string>NO</string>
<key>port</key>
<string>389</string>
<key>type</key>
<string>ldap</string>
</dict>
</array>
<key>WOPort</key>
<string>20000</string>
</dict>
</dict>
</plist>

May this one be related to http://www.sogo.nu/bugs/view.php?id=192 ?

Suspended, shouldn't happen anymore as it was fixed years ago.