I did a search on Google for HP8410 and found several good references including an 8410 Owning and Operating Manual in pdf. I worked on that instrument in my old days at WJ. I did automation work with the old 11863T program to run this system. I completely rewrote it for lots of options. it's been a long while. The docs gave me a refresher and you need a 8411A Harmonic Converter and a reflection/transmission test set.
From doc: The 8740A, 8741A and 8742A are the earliest test sets. The 8740A is a reflection test set, the 8741A and 8742A are transmission test sets. or the Sparamters Test set for forward and reverse Refl/Tran 8745A,46A,47A,48A S-parameter test sets
Own/Op Manual Link: http://www.caip.rutgers.edu/~kahrs/papers/mud2k.pdf
Paper on Older VNA's: http://www.prc68.com/I/MWTE.shtml
On older instruments, the issue for Agilent is the cost to scan the documents and maintain them. I have been saving an archive of App Notes, Manuals etc for many years and have many of the old and no longer available ones from Agilent and some others.
I can also send files by email if you fail in the websites and I have a couple others. Good luck.