How to avoid reloading prototype icon when string paramater in C/C++ adapter?

Question

I have a function in my C++ DLL.
static BOOL InitializeConnection(unsigned char* receivedData, unsigned int* receivedDataLength,
                                                  ​               unsigned int* errorCode, unsigned char errorMessage[512]);
I would like to use a string for the last parameter. When it loads the prototype of function, the type is unsigned char [].
When I enter my Locals.str, it give me the error "Expecting nothing, array of number or array of booleans. Found string"
If I change in the right panel the Category to String and select the Type "C String Buffer", the error goes away and I receive the string value correctly from my dll.
However, I have the red '!" icon flashing next to my function name that says I need to reload the function. Is there a way to get rid of it? I don't want other programmers on my project to hit it and lose all the configuration.
 Also, do I need to do something special so when it loads the function, I dont get "arg1, arg2, arg3" as parameter name but the one from my dll?
I usually program in C# and it loads correctly the right parameters name.
Thank you.
-Mat, CTD

Answer 1

Thanks for the answer Adri.
I got rid of the red ! by switching to char instead of unsigned char.
For the second part, not being able to see the parameter names, I do use the __declspec(dllexport) at the class level. I switched to the way explained in the tutorial without any difference.
class DisplaySeriesComm : public CWinApp
public:
    DisplaySeriesComm();
    ~DisplaySeriesComm();
    static BOOL OpenInterface(CCommunication* ptrCom, signed int* errorCode, char errorMessage[512]);
    static BOOL CloseInterface(CCommunication* ptrCom);
    static __declspec(dllexport) BOOL InitializeConnection(unsigned char* receivedData, unsigned int* receivedDataLength, signed int* errorCode, char errorMessage[512]);
I have access to the function in TestStand, the parameters load with the correct types (the column: Description). It's only the names which are set by default to arg1, arg2, ...
By comparing to the tutorial, the dll I used is an MFC dll and it also uses a .def file. Not sure if it could be related to that.
Thanks.