Progress Bars vs. Meters

Until now I always used the "msctls_progress32" class for progress bars. It's easy to use and works fine. The drawback is that it only supports two "styles". (either the "block" or the "smooth" fill-type)

I know there exists a different type of progress bar, which can be configured in more ways. (like showing text in the progress bar moving with the actual position)

I found out that this type uses the class type "meter" instead of "msctls_progress32". However, the PBM_* constants from my WINDOWS.INC did not work to control the "meter" bar (which was no big suprise).

By debugging some programs which use this type of progress bars I found out that the "meter" bar is controlled by some parameters which are in the same range as the PBM_* constants (WM_USER+???), but work different.

My first guess was that the "meter" class is nothing which COMCTL32.DLL supports by default, but I couldn't find any calls to "USER32.RegisterClass" in the programs I debugged. I also think it's a bit strange that all the programs I tried would call this bar "meter" if they all had to individually create this class.

Am I working in a completely wrong direction or where is my mistake?