I finally got the hardware watchdog working on my Soekris Net4511. The Soekris box runs my webcam and X10 stuff. I installed Voyage linux on the box. The default sc520_wdt does not work with the watchdog on the Net45* boxes. I found a patch to apply. I didn't write the patch, I found it from a post by Jakub Schmidtke.

Update: It turns out Punky does have this patch in the default build of Voyage linux. I just happened to download a snapshot of voyage that didn't include the patch. Anyway if you want watchdog support on a net4511 give voyage a try. It is a pretty good distro.