To use the C or C++ API of SignDoc SDK in a Windows Store app, perform the following steps in Visual Studio:

• Click Project->Add Existing Item..., then browse to SPSignDoc_5.0_app.dll and click Add.
• Repeat for SPFreeImage_1_app.dll and SPTiff_40_app.dll.
• For C and C++ projects, add the directory containing SignDocSDK-cpp.h and SignDocSDK_c.h to the additional include directories (Properties->C/C++->General) and add the directory containing SPSignDoc_5.0_app.lib to the additional dependencies (Properties->Linker->Input).
• Do not use SignDoc SDK in the UI thread.
• You can use only pathnames which point into the ApplicationData.LocalFolder or Package.InstalledLocation directories. For all other pathnames, you have to load the file into memory and pass it as blob into SignDoc SDK or save to a blob and then save that blob to the target file.