How to get friend's detail information

Hi,

I have create some users on the admin web page, and add some users as friend without nickname on the same page.
Then I try to get the rosterentry, and there is no name string in, so I want to get the friend’s realname which is set by register, but only an empty node to show like this:

<iq to='test5@case01' id='31p07-12' type='get'><vCard xmlns='vcard-temp'/></iq>

No name, email and any other information, how to get the correct information? Could you give me some help, thank you!1588001257593