Access Cisco Unity Express from the internet with private addressing

Your Cisco Unity Express Voicemail system is connected to your Cisco Callmanager Express via private addressing? And you need to access it via the Internet? No VPN available?
Well, I had this task waiting for me. Not really complicated, but somebody might find it useful ....

interface GigabitEthernet0/0

 description Internet

 ip address 1.2.3.5 255.255.255.248

 ip nat outside

!

interface ISM0/0

 ip unnumbered Loopback0

 ip nat inside

 service-module ip address 172.20.20.2 255.255.255.252

 !Application: CUE Running on ISM

 service-module ip default-gateway 172.20.20.1

!

ip nat inside source list CUE_OUT interface GigabitEthernet0/0 overload

ip nat inside source static tcp 172.20.20.2 80 1.2.3.5 9999 extendable

!

ip route 0.0.0.0 0.0.0.0 1.2.3.4

ip route 172.20.20.2 255.255.255.255 ISM0/0

!This gives your CUE access to public services (SMTP, DNS, ...)

ip access-list extended CUE_OUT

 deny   ip host 172.20.20.2 host 172.20.20.1

 permit ip host 172.20.20.2 any

Now you only need to enter this URL in your browser:
http://1.2.3.4:9999/admin

If there is a firewall in between , filtering all ports except for SIP traffic & SSH), you could set up an SSH Tunnel to fix that problem. See http://uc-b.blogspot.com/2011/07/putty-scp-file-transfer-to-cisco-ios.html