[sylpheed:36426] add phone number o addresbook entry

[Joe Koenig]

Hi.

How is one supposed to add additional data to a given addressbook
entry?  E.g.: add a phone number to an existing addresbook entry.

I.e.: I'd go 
Tools
 --> Address Book 
   --> Auto-registered Addresses
     --> right-click
       --> 'Edit'

Well, I'm stumped from here on.
I did try "User Attributes -> Add", of course.  To no avail,  It
didn't stick.

Regards Joe

$ sylpheed --version
   Sylpheed version 3.5.0
$ uname -a
Linux Jessi 4.4.1-2-ARCH #1 SMP PREEMPT Wed Feb 3 13:12:33 UTC 2016
x86_64 GNU/Linux