Getting autogenerated files as project artifacts

I am trying to get files generated by our project at compile time; in Perforce those files are not in depot, but only in my workspace.

After I have created a new artifact on TeamCity and specified the path of those generated files, during the build TeamCity throws the error that those files couldn't be found.

I have two assumptions about it:

It's either because files are not in Perforce depot, and TeamCity can't see them (however I was told by my coworkers that it shouldn't be a problem).

Or because of the files naming:

_NAPI.Generated.cs

_Defines_H.Generated.cs

_LIB_H.Generated.cs

_SoftwareDownloadDefines_H.Generated.cs

Maybe TeamCity somehow skips thus files because of underscore in front of the name.

Any help/support/suggestion is greatly appreciated.

Thanks,

Stan