The is my conclusion of 2 weeks hard work trying to submit my own x32 and x64 windows UE4 game to Windows Store:
1.Desktop App Converter [Project Centennial] - Failed
2.Desktop Bridge Sign Up Form - Failed
3.UWP in UE4Editor - coded by Microsoft - Succeed:
“MICROSOFT-XBOX-ATG/MICROSOFT_UWP_UNREAL”
GitHub DOT com/MICROSOFT-XBOX-ATG/MICROSOFT_UWP_UNREAL
Unreal Engine 4 is available for Win10 UWP app dev now
forums DOT unrealengine DOT com/showthread.php?118375-Unreal-Engine-4-is-available-for-Win10-UWP-app-dev-now
Using the third way I managed successfully to convert to UWP64,UWP32 and submit with correct validation in Windows Store