Is there a registry key for "delete meeting request from inbox when responding"

[Ton Danon]

Situation:
Outlook 2000
When you access Tools/Options, then click on E-mail options button,
then click on Advanced E-mail Options button, you enter a form where
you can set some specific behaviour of Outlook.
The last option in this form gives the possibility to switch ON/OFF
the "delete meeting request from inbox when responding" option.
Problem: this options is switched on, and I cannot switch it off, as
for some reason this entry is not changeable for me.
Is it perhaps possible to change a registry key in order to switch
this option to the off situation ?
Which registry key could this be ? Up to now my searches with Google
did nog give me enough information to determine a key like this.

regards,
Ton