Hi Dimon87,
The code interface node is very rarely used and therefore there isn't a lot of documentation about it. Since you already have your code written, I would really recommend compiling your code into a DLL and call it using the Call Library Function Node. For your reference I am attaching a few links that talk about using the Call Library Function Node.
http://zone.ni.com/reference/en-XX/help/371361D-01/glang/call_library_function/
http://zone.ni.com/reference/en-XX/help/371361D-01/lvexcodeconcepts/configuring_the_clf_node/
In addition please look in the example finder for an example called Call DLL.vi It gives a very extensive explanation about using this function.
Eli S.
National Instruments
Applications Engineer