[H] Killing the new Firefox PDF viewer

[Thane Sherrington]

Does anyone know how to turn off Firefox's new PDF viewer?  I use 
Sumatra PDF, and I don't want Firefox to open PDFs in it's own viewer 
(I'm not sure how this was a required feature).  I've gone into 
options and applications, and set it to ask, but that doesn't change 
it.  Any ideas?

T