class pBack : public WithpBackLayout<TopWindow> {
public:
		  		
     typedef pBack CLASSNAME;
     pBack();
     ~pBack();	
     
     void FazBackup();
     String salvaRegsNoZipFile()
	
}	

Gate2<int, int> WhenProgress; //tipo definido          
int ab(int a,int b){          
  float f= static_cast<double>(a) / b * 100;

  //--> here if i put an ProgressIndicator i can't compile !

  return WhenProgress(a,b); //função tem que retornar este tipo          
}

String pBack::salvaRegsNoZipFile()
{
  FileZip zip(fnZip_);
 	FindFile fff(rrTP[i].nArquivo);
	zip.WriteFile(LoadFile(fff.GetPath()), fff.GetName(),ab );
	zip.Finish();
}

void pBack::FazBackup()
{

		Thread thr;
		thr.Run ( [=]
		{
			...
			
			salvaRegsNoZipFile();
			
			...
			
		}
}