[PS] C:\tmp\ps1>$a = get-aduser novap |select givenname,surname
[PS] C:\tmp\ps1>write-host $a
@{givenname=petr; surname=novak}
[PS] C:\tmp\ps1>$b = $a.givenname + ' ' + $a.surname
[PS] C:\tmp\ps1>$b
Petr Novak
[PS] C:\tmp\ps1>
.. tj. proměnnou $b můžeš přes set-qaduser vložit ..