Outlook Calendar

Hi folks,
a slight problem. I noticed recently that my invitations are going into a
new Calendar mysteriously created in my pst files.
Here's the scenario
Incoming meeting > Rule Wizard FWD to folder setup by me for mails from
this person. > I accept invitation > Goes into pst calendar.

I would prefer it to go into my mailbox Calendar. (Automatically - not via
copy)
Can anyone Help,

thanks,

Chris