Usually there are 2 build modes preconfigured: a debug and a release mode. Open in UEStudio
Project - Project Settings and switch to tab
Settings. On bottom right corner you can select which version is created on build, the debug or the release version. The build version can be also selected from BUILD toolbar. Click on button
Compiler Options to open the options dialog. You can set there at bottom the directories used for the debug version and for the release version. Usually subdirectory
Debug in project directory is used for the debug version and
Release for the release version. You can enter here any relative or absolute path.
You need to build the debug version of your plugin DLL. And for debugging the DLL, it is necessary that
your dll.pdb is in the same directory as the DLL. You have to configure in Vissim either the path to your plugin in the Debug directory or you change in the compiler options that debug directory is the directory where Vissim expects your plugin DLL.
You don't need all the symbol files of Windows libraries and of Vissim do debug your plugin DLL. So ignore all the warnings of Windbg about the missing symbol files.
By searching for
Windbg debug "plugin DLL" with Google I found several articles about how to debug a plugin DLL. Perhaps one of them is useful for you. What you should avoid is that Vissim loads any other plugin than yours to make debugging your plugin easier.
If you think you don't need step by step debugging, it might be easier to add to your plugin code which prints messages into a file with fixed path to create a pseudo debug log with enough information to find out what is going wrong. Alternatively you could just add TRACE commands to your code and use
DebugView of SysInternals to get a log of all debug messages from within your plugin.