The version of eyebeam we're using has an option listed as "Number for sending calls to voicemail". I haven't been able to discover the right string to input here for 3CX. For example, there is a setting for "Number to dial for checking voicemail", which works with "sip:firstname.lastname@example.org". For the "Number for sending calls to voicemail" option, I've tried "sip:*email@example.com", "sip:firstname.lastname@example.org", "sip:email@example.com" -- none of which directs the caller to my (ext 100) voicemail to leave a message. I searched the forums and manual, but couldn't find this referenced anywhere.