the correct project type in the project symbol POC_PROJECT_TYPE is important for the IDE in some cases (like this one). I might add some form of conversion in the future, but for now the easiest way is probably to (caryfully) edit the PPJ file directly using some editor.
Here is the list of known project types (from wizard.h):
enum WizProjType {
Project_Win32_GUI = 0,
Project_Win32_DLL = 1,
Project_Win32_Library = 2,
Project_Win32_Console = 3,
Project_WinCE_Pocket_PC_GUI = 4,
Project_WinCE_Pocket_PC_DLL = 5,
Project_WinCE_Pocket_PC_Library = 6,
Project_WinCE_Smartphone_GUI = 7,
Project_WinCE_Smartphone_DLL = 8,
Project_WinCE_Smartphone_Library = 9,
Project_Win64_GUI = 10,
Project_Win64_DLL = 11,
Project_Win64_Library = 12,
Project_Win64_Console = 13,
Project_Win32_Installer = 50,
Project_WinCE_Pocket_PC_Installer = 51,
Project_WinCE_Smartphone_Installer = 52,
};