I have a skype button on my web page. It works fine if I'm logged in with a skype client on a PC. However, most of the time I use a phillips VoIP 8551 dual line phone. I'm logged in all the time, however the web site shows my button as offline. The privacy setting on the profile is of course set to allow to see my status online.
check out this link for help with that.
PARKERTEK Computer Services