Kannel & USSD status

Hi,

I'm in the process of setting up USSD -> web application integration 
with a mobile telecoms provider (I have SMPP 3.4 based access to their 
gateway, and they support USSD messaging).

While looking at options for setting this up, and kannel came up, 
however looking through the mail archives it's not entirely clear that 
USSD is supported out of the box with Kannel, potentially requiring 
patches/recompilation.

I've got  kannel  1.4.4-4 running on a debian 9 machine, and connect to 
that via a python smpp client library, however I can't seem to figure 
out how to simulate initiating a USSD session.  Are there some command 
line tools/clients that can do this or is more a case of write your 
own?  I've spotted fakesmsc but can't see how to generate ussd traffic 
from that.

Ideally I'd like to configure kannel/smsbox/sms-service to call into an 
HTTP api with a session id/phone number/subscriberid - so that I can go 
back and forth between the user and my server to get answers to a few 
questions.

Using SMPPSim's inject_mo I can simulate SMS and SMS responses already 
to my HTTP based application server.

Thank you very much for any pointers in advance,  I attach my current 
config below.

Damian


group = core
admin-port = 13000
admin-password = bar
admin-deny-ip = ""
admin-allow-ip = "*.*.*.*"
smsbox-port = 13003
wdp-interface-name = "*"
log-file = "/var/log/kannel/bearerbox.log"
box-deny-ip = "*.*.*.*"
box-allow-ip = "127.0.0.1"

group = smsbox
# smsbox-id = mysmsbox
bearerbox-host = localhost
sendsms-port = 1025
global-sender = 1000
log-level = 0
log-file = "/var/log/kannel/smsbox.log"
mo-recode = true
sendsms-port = 13013

group = smsc
smsc = smpp
smsc-id = SMPPSim
host = 10.10.10.1
port = 2775
transceiver-mode = 1
smsc-username = smppclient1
smsc-password = password
system-type = 'VMA'
#service-type = 'test'
interface-version = 34
system-id = smppclient
preferred-smsc-id = SMPPSim

group = sms-service
keyword = default
# get-url = "http://localhost:8000/api/v1/sms/?phone=%p&text=%a"
# accept-x-kannel-headers = true
post-url = "http://localhost:8000/api/v1/sms/"
catch-all = true

group = smpp-tlv
name = ussd_service_op
tag = 0x0501
type = integer
length = 1