16 bit PC card and win XP

Hy,
I have an Inspiron 8200, WinXP (SP1), BIOS A10.
My PCMCIA slots work fine with cardbus PC Card.

I would use a 16 bit PC card (5 volt, the “old” type).
This appears impossible.

Following this forum, I understand that Win XP SP1 does not allow 16 bit Cards because it turns off PCI to ISA IRQ routing in the registry.

I “hacked” the registry:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Pcmcia\Parameters]
"SoundsEnabled"=dword:00000001
"IsaIrqRescanComplete"=dword:00000000
"DisableIsaToPciRouting"=dword:00000000

but, after a reboot or after than the XP installs PCMCIA cardbus controllers, the registry became:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Pcmcia\Parameters]
"SoundsEnabled"=dword:00000001
"IsaIrqRescanComplete"=dword:00000001
"DisableIsaToPciRouting"=dword:00000000

and it is impossible to recognize my card.

I suspect that the 16 bit (PCIC) compatibility is lost when XP installs the cardbus drivers: but this is automatic: how I can disable plug & play? How I can avoid that XP automatically installs cardbus drivers?

Thanks for helps !

Augusto