JNAerator generates method with __stdcall return value

Question

I'm currently struggling to generate a JNA wrapper for a DLL that I have to use. The DLL and the corresponding .h files are provided by IBM (Spectrum Protect aka Tivoli Storage Manager or ADSTAR) and for the life of me, I cannot use JNAerator properly, as it seems.

Example:

This is an excerpt of one of the header files:

extern dsInt16_t DSMLINKAGE  dsmInitEx(
       dsUint32_t            *dsmHandleP,
       dsmInitExIn_t         *dsmInitExInP,
       dsmInitExOut_t        *dsmInitExOutP
);

This dsInt16_t turns out to be defined in a separate .h file:

typedef signed   short dsInt16_t;

The result after running JNAerator is not what I would have expected:

Tsmapi64Library.__stdcall dsmInitEx(NativeLongByReference dsmHandleP, dsmInitExIn_t dsmInitExInP, dsmInitExOut_t dsmInitExOutP);

The return type is defined as follows:

public static class __stdcall extends PointerType {
...
};

Mind you, last time I worked with C was in school, and that is 20+ years ago, so I am definitely a bit rusty.

What am I missing here? I would have hoped that the return value would be a dsInt16_t or short, for example.

A follow-up question: the DLL provides a method for explaining return codes (the aforementioned dsInt16_t return value).

Again, this is the definition in the .h file:

extern dsInt16_t DSMLINKAGE  dsmRCMsg(
       dsUint32_t            dsmHandle,
       dsInt16_t             dsmRC,
       char                  *msg
);

...and this is the resulting Java code:

Tsmapi64Library.__stdcall dsmRCMsg(NativeLong dsmHandle, dsInt16_t dsmRC, ByteBuffer msg);

So, it "translated" the C-parameter type dsInt16_t into the Java type dsInt16_t, which is nice. Since this Java type dsInt16_t is an interface, how would I be able to create an instance of this type so that I could actually call the method? (I guess this question is obsolete once the first one is resolved.)