Problems with Matlab-MEX files (McsUsbDLL.h) on 64Bit for STG400x

I try to use an STG400x with Matlab (R2011b) control with a 64Bit WIN 7 computer.
Even with Microsoft SDK 7.1 installed (like suggested by Matlab for the compilation of MEX files) Matlab still fails to deal with the MEX files.
If I understood it correctly Matlab tries to compile the McsUsbDLL.h file, which is written in C++. Therefore Matlab requires a compiler to deal with it. However it fails with SDK 7.1.
Is there a solution to that problem?

You probably have 64bit Matlab.
Our McsUsbDLL.dll is a 32bit DLL, so calling functions from a 64bit process will fail.
Jens