Hi Mayo,
I don't use Safari much, but I can tell you that Reader 8.1 has been a pain in the rear end with Mozilla SeaMonkey. No matter what I do, or how many times I reset the helper application preferences, the program will not accept the change in the preferences panel. Now this is in Tiger, 10.4.10. So when I try to open an attached .pdf, SeaMonkey can't find the helper application.
Now either Jennie or Paddy posted a link for a program called PDF Browser Plugin, and that has been the only way that SeaMonkey will recognize Reader 8.1
I'm going to much around in the TS site and see if I can find it, or I can e-mail it to you if I can't find the post. I'll put in a new reply in this thread if I find the link.
HTH,
Chris K
EDIT: Mayo, this is unfortunately a plug-in only for Mozilla products, posted by XABD...