First off: I'm not sure if this should be on superuser or here.

I have recently built a few Asterisk boxes with OpenVOX FXO/FXS ports little or no trouble.

My current project is building an Asterisk box with SIP trunks. My current employer insisted on getting Skype Business/Skype connect for that purpose. After reviewing the Skype Connect plan, I agreed, because I thought it is going to be straightforward: Purchase G729 licences and setup SIP trunk/trunks.

Boy was i wrong :)

Here is the setup:
The setup is for calling US numbers only via skype (we got skype US minute bundles in skype connect)
AsteriskNOW - Asterisk 1.4 + asterisk-gui
Trunks: SIP Trunk configured with Skype Connect - shows as registered
Users: 2 test extensions. Both work fine when calling each other, voicemail etc works fine too
The asterisk box is behind a Mikrotik router which i configured to forward all relevant ports: 5060-5090 UDP, 10000-20000 UDP. When trying out an extension outside of my LAN, it worked. I could make calls to the other extension.

Outgoing rule: _NXXXXXXXXX
Strip:0
Prepend:+1
Use skype trunk

Inbound rule:
Trunk: Skype
Pattern: s
Destination: Extension1 (6210)

Here is the output of asterisk CLI (-rvvvvv) with outgoing calls:

http://pastebin.com/eWVpL72e

you can see the circuit-busy response when using trunk1 (skype)

When calling my Skype Connect number from the outside, I get nothing in the logs.

Can anyone with Skype Connect / Asterisk experience help out? :)