Arduino Programmable Clock + ENC28j60 ethernet shield

I have already made a working project that basically turns on/off an appliance using a web interface using ENC28j60 as an Ethernet Shield. As an additional feature, I would like to add a scheduled timer to my webpage to control. Problem is I can't integrate the Arduino Timer Library or with my Ethernet Shield's Library. I also can't find anything in Google remotely similar to my problem. Any suggestions?

Problem is I can't integrate the Arduino Timer Library or with my Ethernet Shield's Library.

Why not?

I would like to add a scheduled timer to my webpage to control.

The Arduino has to serve up some html. What would a "scheduled timer" look like when rendered by your client/browser? What have you made the Arduino send? Are you able to get something back from the client (a new GET request when something is clicked on the form)?