BUG? Duplicated entries in "Add/Remove Program"!

hi,

We have made an installer which would use msi for installation and a
customized uninstall.exe for the uninstallation. In order to use the
customized uninstall.exe, we have config these two registry values
under this key:

KEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Curre ntVersion\Uninstall
\{1389C6A4-4965-4AEC-9175-08B54A10FA48}
UninstallString = "path_of_the_customized_uninstall.exe"
WindowsInstaller = (DWORD)0

But this cause a bug under Windows XP:
There would be two same entries for this software in "Add/Remove
Program". And, while clicking "uninstall" button of them, the first
one will use the customized uninstall.exe but the second one will use
"msiexec.exe" to uninstall the software.

Actually, we only need one entry (which use the customized
uninstall.exe for uninstallation) for our software displayed in ARP.
Can any one please help with this problem?
Any feedback, suggetions, comments on this will be appreciated.

Best regards,
ZZT ,waker615@gmail.com