we are developing nowadays system called "  Electronic Case Management  " for government department  , this department  has Service Desk Plus System 

we need integrate with Service desk plus as next : 

1- when request is created in service desk plus , we create request in our system 

2- when update the status of the request in service desk plus ( from open to on-hold or resolved or rejected or closed ) , we need update the status of the request in our system 

3- when  action performed on the request in the Service Desk Plus , the information of action is seen to the requester in our system

 

4- when the request require approval from Direct Manager of requester , we need the approval process to occur in our system and the result of approval ( approve or reject ) will be sent back 

and registered in service desk plus system

5- when technician add notes on the request  , the requester can see these notes on his page in our system and also  the replies to these notes returned and registered in service desk plus 

system

my question is , how we can achieve the mentioned integration points in detail , we use web service in integration with third party. i read about Custom Trigger feature in service desk plus.

please help me 

thank you very much