Hi Chris,
You have an option to use the Interactive Voice Response menu (IVR) to enable web management of the spa9000.
Check IVR options in the admin guide but try the following, hope i got it right :)
Step 1. plug a analogue phone onto green "phone 1" port
step 2. press ****
a female voice will say something like "select menu option" or try pressing **** again
Step 3. press 110# to hear and confirm your management IP address
step 4. press 7932# (this will enable or diable the web management server, and follow the directions)
Step 5. then press 1# to enable web management and 1 again to save your option.
This is off the top of my head, so double check with the SPA9000 Admin guide under the IVR option.
Hope this solves the issue.
regards Dave