Created attachment 31136 [details]
Empathy/Gabble just shows the username for contacts when using my university's XMPP server instead of the data from the vCard as Pidgin does.
The server in use is ejabberd, version 2.0.3 I think. User accounts (and vCards) are created automatically using the univerity's LDAP.
Created attachment 31137 [details]
Your log demonstrates that Gabble looks up the XEP-0045 (vcard-temp) vCard, but (as seen for Roman Komp in your log) it doesn't find anything:
gabble/vcard-DEBUG: 1.258042e+09: gabble_vcard_manager_request: Created request 0x8cb9e40 to retrieve <5>'s vCard
gabble/vcard-DEBUG: 1.258042e+09: request_send: Cache entry 0x8cb9e60 is not mine, @to = firstname.lastname@example.org
gabble/vcard-DEBUG: 1.258042e+09: pipeline_reply_cb: successful lookup response contained no <vCard> node, creating an empty one
gabble/vcard-DEBUG: 1.258042e+09: observe_vcard: got no vCard alias for handle 5
I'd have expected the LDAP data to appear in these vCards, since that's how XMPP clients typically derive users' names.
However, I notice your server has a "user directory" attached, vjud.jabber.uni-koblenz.de. Is that where the LDAP data is? Does Pidgin get data from that instead/as well?
If so, then that's something that Gabble doesn't do. In principle it could, although I'm a bit reluctant to make Gabble expend even more bandwidth on trying to identify people...