Login problems with LDAP

Hello, I have browsed through the questions in the forum, but I could not find an answer to my problem.
I shall try to describe it and maybe somebody can point me to the right discussion.

Very simply said we are using RTC 4.0.1 on a VmWare server which uses Windows Server 2008 R2.
The database we are using is MS SQLserver express 2008, as it should be enough for our purposes, for the time being.
We have tried to connect our server to our domain LDAP server, but we currently cannot login in RTC by using the imported users.  We always get the message "Invalid User ID or password". We are not using WebSphere.

I am enclosing a portion of the teamserver.properties, in the hope it can help others understand if we are doing something seriuosly wrong. I see other people having no problems in logging in using LDAP, so we would like to do it as well.

------------------------------------------------------------------------------------------------------------------------------------
com.ibm.team.datawarehouse.auth.type=JTS
com.ibm.team.repository.ldap.membersOfGroup=member
com.ibm.team.repository.db.jdbc.location=//ceres\:1433;databaseName\=jts;user\=jtsDBuser;password\={password}
com.ibm.team.datawarehouse.auth.userId=028388bc6fd94b7db921f8187ded60d0
com.ibm.team.repository.changeEvent.expirationByCategory=SystemLog\:259200
com.ibm.team.repository.RLSTokenService.tokenLicensePath=19353@bianca
com.ibm.team.repository.ldap.baseUserDN=ou\=UserTSMT,dc\=tsmt,dc\=net
com.ibm.team.datawarehouse.db.jdbc.location=//ceres\:1433;databaseName\=dw;user\=dwDBuser;password\={password}
com.ibm.team.repository.notification.mail.smtp.server=tsmtmail.tsmt.net
com.ibm.team.fulltext.indexLocation=conf/jts/indices/workitemindex
com.ibm.team.repository.web.helpuri=/clmhelp/index.jsp
com.ibm.team.repository.diagnostic.dnsResolutionDiagnostic.externalHostname=tsmt.net
com.ibm.team.repository.db.jdbc.password=[k0Hdl4yYF5/VhPT0IKeV3w\=\=]
com.ibm.team.repository.ldap.userAttributesMapping=userId\=cn,name\=displayName,emailAddress\=mail
com.ibm.team.repository.notification.mail.from_name=jazz
com.ibm.team.repository.notification.mail.from=Jazz@tsmt.net
com.ibm.team.repository.notification.mail.enabled=false
com.ibm.team.datawarehouse.db.jdbc.password=[z30UFj2BBvaqhIZHiC9JRg\=\=]
com.ibm.team.repository.db.repoLockId=_ZD2KUDk5EeKYmfO0PQ739A
com.ibm.team.repository.user.registry.type=LDAP
com.ibm.team.repository.ws.allow.identity.assertion=false
com.ibm.team.repository.ldap.registryLocation=ldap\://tsmtdom1.tsmt.net\:389
com.ibm.team.datawarehouse.auth.password=[nVljcwAbVUnJFFJU47Aq0MYvATN3hVdYbnuMeSS9eIluZ4R66KIsDqOD47eGgist]
com.ibm.team.repository.ldap.baseGroupDN=ou\=JazzGroup,dc\=tsmt,dc\=net
com.ibm.team.repository.notification.mail.reply=fontana@tsmt.net;viano@tsmt.net;digiandomenico@tsmt.net
com.ibm.team.repository.changeEvent.expirationDefault=1209600
com.ibm.team.repository.licenseService.floatingLicenseServerURI=https\://ceres\:9443/jts/
com.ibm.team.repository.tokenProviderService=com.ibm.rational.common.token.licensing.RLSTokenService
com.ibm.team.repository.ldap.findUsersByNameQuery=displayName\=?1*
com.ibm.team.repository.ldap.registryUserName=jazz_admin@tsmt.net
com.ibm.team.repository.web.suppressedPages={"com.ibm.team.repository.web.admin"\: ["com.ibm.team.repository.provision"]}
com.ibm.team.datawarehouse.datawarehouse.jobs.enabled=true
com.ibm.team.repository.setup.completed.setup=true
com.ibm.team.repository.ldap.registryPassword=administrator
com.ibm.team.repository.server.webapp.url=https\://ceres\:9443/jts
com.ibm.team.datawarehouse.db.automatic.setup=true
com.ibm.team.repository.db.vendor=sqlserver
com.ibm.team.repository.ldap.findUsersByUserIdQuery=cn\=?1
com.ibm.team.jfs.index.root.directory=indices
com.ibm.team.datawarehouse.db.net.port=1527
com.ibm.team.repository.ws.allow.admin.access=false
com.ibm.team.repository.ldap.findUsersByAnyNameQuery=(| (displayName\=* ?1*) (displayName\=*_?1*))
com.ibm.team.datawarehouse.db.vendor=sqlserver
com.ibm.team.datawarehouse.datawarehouse.provider=Remote
com.ibm.team.datawarehouse.db.base.folder=C\:\\RTC
-------------------------------------------------------------------------------------------------------------------------

Thanks in advance for any help.

Bruno