Hello,
There may be several approaches, i am just listing a few.
1. scan the tape with scanner cmd, just briefly to introduce it to the 
mbB, once you have done that, you can then query the tape for ssid, match 
up the ssid for the client you want to recover and do the ssid recover.
2. Have you tried using FQDN for the client in question ? during recover ?
3.You may have to increase the BP and\or retention policy to browse old 
indexes depending on how they are setup now, once you do that you may use 
nsrck -L7 with t switch to recover old index .
HTH

To sign off this list, send email to listserv AT listserv.temple DOT edu and 
type "signoff networker" in the body of the email. Please write to 
networker-request AT listserv.temple DOT edu if you have any problems with this 
list. You can access the archives at 
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER