UPnP Port Forwarding / Mapping

Hi everyone,
 

 I've developed a product using a RCM4300 board that hosts an embedded web page to show some parameters of a machine (pressures, temperatures, etc...).
 

 In 90% of the cases the connection scheme is RCM4300 -> (Router ->) Modem -> Internet. No big companies with IT departments... it's just like a home connection, because the machines are in the field.
 

 In order to be able to access the board from the internet, the RCM4300 has a static LAN IP address (for example 192.168.1.50) and the user needs to map the port on the router (for example forward external port 12345 to 192.168.1.50 : 80). This works fine.
 

 I want to do the mapping of the port from the RCM4300 board using UPnP. I think it's possible because I've found an example for Arduino (I haven't tried, though). 
 

 Before developing a library I would like to hear your opinion about this matter as I think it's a very common situation that many of you may have experienced. May be the library is already developed or may be there is a downside I haven't considered...
 

 Thank you for your help!
 

 
 Agustin