Using ShellExecute with hh.exe and parameters (Delphi 3)

I am having problems passing a .CHM file mapID value into a ShellExecute procedure.  Although the .CHM file launches, the context ID (mapID) page does not appear as the default.  Here's the code I'm using...

HelpNullFile: Array[0..128] of Char;
Instance: THandle;

begin

StrPCopy(HelpNullFile, ExtractFilePath(Application.ExeName) + 'help.chm');

Instance := ShellExecute(Application.Handle, 'open', HelpNullFile, PChar('-mapid 5'), nil, SW_SHOWNORMAL      );

end;

If I go to a DOS prompt, and type...

hh.exe -mapID 5 help.chm

... the correct page appears.  How can I get the correct page to appear when launched within Delphi 3?Start Free Trial