Yes Driss I have LDAP Integration and is in sync. with Call Manager and I add this field and it is synced to CUCM but do not appear in the user Profile for the user.
There is no way to add custom fields, or rename the fields, you can only adjust the mapping of the ones available. The directory integration chapter of the Jabber documentation has all the details.
May be try changing the default mapping or make sure that the proper ldap attributes are populated
Sorry, the version was 11.5 and not 11.8... it's why ^^
for the 11.8 version: http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/jabber/11_8/cjab_b_parameters-reference-guide-jabber-118/cjab_b_parameters-reference-guide-jabber-118_chapter_01010.html
And of course, CDI is really appreciated :)