Sorry, I can’t help with that.
See the latest PTS http://developer.sierrawireless.com/Resources/Resources/AirPrime/Hardware_specs_user_guides/AirPrime_SL808xT_SL808xBT_and_SL808xBTA_Product_Technical_Specification_and_Customer_Design_Guidelines.aspx for GPIOs & ADC. PTS also mentions USB CDC-EEM class, which may be an alternate option for your Ethernet requirement.