bind UID in DN instead of CN

[Dennis <openldap@wehrle.it>]

Hi everyone,

I'm new to the ldap stuff, therefore sorry if this is a silly question. 
My openldap (slapd) version is 2.4.28. To manage openldap I'm using 
phpldapadmin. I'm using a third party software which relies on ldap to 
manage users.

I've added a test user to ldap via phpldapadmin. The 3rd party software 
tries to modify/add an object via the following bind:

slapd[19030]: conn=1435 fd=18 ACCEPT from IP=X.X.X.X:35541 (IP=0.0.0.0:389)
slapd[19030]: conn=1435 op=0 BIND dn="cn=admin,dc=dmp,dc=..." method=128
slapd[19030]: conn=1435 op=0 BIND dn="cn=admin,dc=dmp,dc=..." 
mech=SIMPLE ssf=0
slapd[19030]: conn=1435 op=0 RESULT tag=97 err=0 text=
slapd[19030]: conn=1435 op=1 MOD dn="uid=test1003,ou=users,dc=dmp,dc=..."
slapd[19030]: conn=1435 op=1 MOD attr=objectclass
slapd[19030]: conn=1435 op=1 RESULT tag=103 err=32 text=
slapd[19030]: conn=1435 fd=18 closed (connection lost)

This fails because it tries to accomplish this by using dn="uid=...", 
but as shown in phpldapadmin the dn is cn=Test 
Testuser,ou=users,dc=dmp,dc=...
Therefore the distinguished name for dn="uid=...,ou=users,dc=dmp,dc=..." 
doesn't exist (the user has a uid of course).
Therefore my question is, is there a possibility to change / to 
configure openldap to use / allow the uid instead of the cn? Or did I 
something wrong? So far I couldn't find any information about this. Any 
help is welcome and I would really appreciate this :)

Best regards and have a nice weekend!
Dennis Wehrle