Yup. A call that is forwarded from station A to station B will not follow a System Forward path. In order for a call to forward to voicemail w\ the Xarios solution, the destination station needs to be station no-answer forwarded to voicemail. Soooo:

Phantom Station: 1000
Physical Station: 1500

Station 1500 has a System Forward path programmed for the voicemail pilot for no-answer calls. I forward 1000 to 1500 and call 1000. 1500 will ring, but never forward to voicemail. This is normal. However, if I station no-answer forward 1500 to the voicemail pilot, calls to 1000 will ring 1500, then forward to mailbox 1000.
Sequence to forward: 'Infinity' key, 356, voicemail pilot number.