You may be hitting:
CSCee33165
In CCM 4.X we no longer need to EDIT the VoiceMailProfiles.xml
http://www.cisco.com/univercd/cc/td/doc/product/voice/c_callmg/4_0/rel_note/402cmrn.htm#wp1866248
"This release reimplements Transfer to Voicemail with JTAPI support. Administrators no longer need to edit the VoiceMailProfiles.xml property file to enable user access to the voice-messaging system from the Cisco CallManager Attendant Console" JTAPI now, knows how to read the system settings.
Transfer to voicemail feature is broken if the Voice Mail Profile is set to NONE under the phone's line setting. When Voicemail profile field is set to NONE, the line will take system default voicemail profile; this configuration does not work.
If the line is reconfigure by selecting the system default voicemail profile, transfer to voicemail from AC client works.
This problem is identical to CSCed71318.
HTH