safe_mode and exec() in win2003 server

Hi, I tried to search this group but found no answer. My environment: win2003 server, apache 2.0.54, php 4.3.11 . When safe_mode is off, calls to exec() go just fine. When safe_mode is on and safe_mode_exec_dir is set properly, no success, but php says otherwise: return code is 0, no error/warning is reported, even with error_reporting(E_ALL). I tried to: allow IUSR_MACHINENAME to exec C:\WINDOWS\system32\cmd.exe; start Apache as an administrative account (not as 'local system account'); copy cmd.exe to C:\PHP; call cmd.exe /C exec_command ... no success. Even exchange '\' by '/' and vice versa, nothing changes. Any help is appreciated. Thanks in advance, Zagab