I no longer see documentation for 6.x releases online, you might want to try the built-in help from CUCM
Otherwise, this might work
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/4_2_3/ccmfeat/ccmfeat/fsccmac.html#wpxref29392
I'm not even sure that the old client will work on a W7 64 bits machine, it was probably only tested up to XP
HTH
java
if this helps, please rate