I have a Proliphix tstat interfaced to Homeseer. I configured one of my touch screen pages, run by MainLobby, to access Homeseer variables to display all the tstat values and allow mode control. I don't allow setpoints to be changed from the MainLobby screen, only AC/Heater on/off. I announce mode changes over the whole house audio.
When I received my first Proliphix last winter, the current temperature reading was fixed at 68 degrees. Instead of putting my old tstat back in until I got a replacement, I used a temp probe I had and setup Homeseer to monitor the indoor temperature and actively turn heating on/off. This actually worked really well since it allowed a configurable temperature band, such as +- 2 degrees, around the setpoint, which the Proliphix I have doesn't do causing it to cycle more often. When the replacement came, I went ahead and let it control the mode, but I'm thinking about beefing up my original setup in Homeseer with some of the ideas here and using that to control the tstat.