Hi there, Call Transfer should work.
If you have REFER supported enabled in the Trunk Configuration, you may try disabling it!

I tried setting Refer to None and it is not allowing a transfer from Skype to Cisco. The Cisco desk phone rings and all I ever hear is some clicking. If I can't get it to work it will just have to be what it is, although I am still hopeful I can
get it to work.