I'm guessing here, but try this way:
Container {
property string pin
Button {
text: "Invite to BBM"
onClicked: {
invoke.query.setUri("pin:" + pin)
invoke.trigger("bb.action.INVITEBBM")
}
}
attachedObjects: [
Invocation {
id: invoke
query {
invokeTargetId: "sys.bbm.sharehandler"
onQueryChanged: {
invoke.query.updateQuery()
}
}
}
]
}