They require some fairly specific .xml files for configuration - search around, there are several articles that detail how to configure them, but you will also need to be running SIP software on them (they are defaulted to skinny protocol) and the SIP software is fairly hard to get anymore (Cisco does not make them easily available).
The Schmooze commercial Endpoint Manager says it supports them here:
http://wiki.freepbx.org/display/FCM/EPM-Supported+Devices
But I have not tried it - I never liked them much on SIP and never spent enough time to get skinny going well enough to say either way.
Greg