With Avaya ACE 6.2 release, RESTFul Messaging API is made available for the developers. Users can retrieve, delete and modify voicemail messages and messaging information through Avaya Messaging service provider.
Please check the 'Messaging Interface' Section of Avaya Agile Communication Environment? Web Services guide for more details.
We have recently made ACE Web Services Trainer 22.214.171.124 available on the DevConnect portal which enables testing of the Messaging API.
Now coming to your questions:
1- sending a voicemail to an Avayaphone
Response--> As of release 6.2, ACE users are allowed to perform Messaging operations only for the message box assigned to them. Operations on any other message box are prohibited. One can retrieve the details for voicemails and even listen to them.
Now for sending a voicemail, you could use Third Party call Control/ Call Extensions to set-up a call. If the called-party is not available and has a voicemail coverage path defined in its configuration at Communication Manager, the call will go to the voicemail. Is this this what you are looking for? If not, please elaborate on your requirement.
2- simulating a phone call and detecting weather a user replied or voicemail
Response-->getMessageFlags operation through boolean values return the status of 'answered|taggesfordeletion|unread|importance|' flags for a particular message.
So based on the true/false value you can determine if particular message was read and replied.
But the the 'simulating a phone call' portion of your question hints that your requirement might be different. Please elaborate.