Digium Dahdi module + Echo Cancellation etc

I just (foolishly) decided to install the Digum Dahdi module for FreePBX which overwrote chan_dahdi.conf

I got Dahdi working again but have a couple problems. The first is that when I make changes in general on the Dahdi page (not to a specific Dahdi card) I get the error “not writable” in small text on the page.

More significantly where can I set things like
faxdetect=both
echocancel=256
echocancelwhenbridged=no
echotraining=no

etc.