Custom Transaction in Mobile ( laptop)

My requirement is to build a custom transaction in Mobile 5.0 ( Laptop solution) which needs to interact with SAP R/3 using RFC function calls.

I am planning to use .Net connector to connect R/3. How do I pass the value back and forth to the function module from screen.

In research I found that I can only use .Net connector in BO layer.

I used tile and mobile is asking me to bind to Bdoc but I don't have one?

highly appreciate your response.