D2.0 cpp interfacing: what is a C++ unsigned long counterpart in D?

[Denis Koroskin]

I'm currently writing a program that interfaces with C++.
C++ code uses a lot of 'unsigned long', which equals to 'unsigned int', or  
just 'unsigned', but is mangled differently.

In particular, C++ mangles unsigned long as 'K', and I can't find a D  
counterpart that would be mangled similarly.
This results in an unaccessible function (it is unresolved at link time).

Any thoughts?