Need help explaining in-addr.arpa to Limelight

[Tuc at T-B-O-H.NET]

Hi,

        I seem to be having a problem. Limelight has SWIP'd 
69.28.185.0/24 to me, and I asked for IN-ADDR.ARPA control.
I recently went to check and it seemed not to be working
right. I sent them an email around 11p Eastern Sunday nite
asking it to be fixed. I even included a reference to a
web page on how to delegate in-addr.arpa.  I received the
following back :

"This is done, but you will need to rename the zone on your
end to: tboh.185.28.69.in-addr.arpa."

        Is there someone out there that might be able
to help me explain this to the techs there. That you
can't "subdomain" an in-addr.arpa like you do a domain
name?

                Thanks, Tuc/TBOH