How to set campaign_am_message_exten???

I would like to drop a prerecoded message everytime the agent gets answermachine or voicemail.

There is a VM button found in the call transfer, whenever i press it to transfer i get these error in chrome inspect... I see goautodial3.3 had vicidial settings to set extension but i cant these settings in 4.0.

PS.. I am using outbound on autodial, amd detection on.. wav file uploaded, amd action yes, waitforsilence set to 2000,2 ..