This forum is for discussing Measurement Studio for Visual C++. For LabVIEW questions about DLL calls, you should use the LabVIEW->General section of Developer's Exchange.
The most probable answer to your question is that you will have to create C style functions as entry points to the DLL that will create you WSDevice object and call functions on it. LabVIEW's Call Library function support C style DLL's.
Best Regards,
Chris Matthews
Measurement Studio Support Manager