Commercial lib static-dynamic msvc10. They say me I only can link dynamic????

I have a commercial libs compiled with msvc10.
The company offers libs compiled with MT, MD option.
I can choose "thelibs_MT.zip", "thelibs_MD.zip" or "thelibs_DLL.zip" .
DLL = Dynamic . MT = static, MD = ???

If you unzip any of the 3 files you have a folder with similar structure, with or witout (depends) libs and DLLS.
They have a QT example projects (multiplatform QT , because I can see win32, linux and mac config options for a pri files)
They say than only dynamic dll link can be used .

Why can it be possible ? If I have QT + msvc10 toolchain .... Why I can't use static link?
Can you undertand it ? Any explanation ?
What is the difference betwen thelibs_MD and thelibs_DLL (internally the folders are almost equal...)

I have asked them without success.... So I hope your help...
Thanks