iPad accessory communication through UART

We manufacture a new accessory for iPad/iPhone which should transfer commands to the iPad. We like to use UART (through a certain Apple-protocol called Lingo). My research shows that I can only use USB (30PIN Connector) and custom protocols.

Question:

• Is there any way to use UART to connect to the iPad accessory from APP side?
• If the protocol is implemented in UART, we should be able to move it to USB, if it's not available to my App via USB.

My main guess is that the UART commands & access are protocols reserved to the iPhone OS and not available to Apps. Certain UART commands also include settings for volumes and Audio re-routing etc, so I guess that's secured.

reference：

Without jailbreak, you will not be able to access UART on iPad/iPod/iPhone as a normal developer. If you need access to the serial port or USB, you need to join Apple's MFi ("Made for iPhone") program and you will get full access to all relevant information. Unfortunately, you'll have to convince Apple that you're doing serious business and have a high volume manufacturing facility at hand (see also this thread).