Rigth now, in order to add a custom task a .wid has to be copied in the same directory than the bpmn or located under global directory in the workspace.
Also, by default, when installing the VS plugin, milestone task is already there.
This JIRA has been opened to do the same that is done for milestone, so REST icon appears in custom task palette without the need for the user of defining its own WID file. Please note that we are providing REstWorkItemHandler out of the box and requesting this to the user will look weird.
Below is the WID definition for REST
[
"name" : "Rest",
"parameters" : [
"Url" : new StringDataType(),
"ContentData" : new ObjectDataType(),
"Method": new StringDataType,
"Host" : new StringDataType(),
"Port" : new IntegerDataType(),
"Username" : new StringDataType(),
"Password" : new StringDataType()
],
"results" : [
"Result" : new ObjectDataType(),
],
"displayName" : "REST",
"icon" : "defaultservicenodeicon.png"
]