How do you set the default "Import Calendar" for VCS files?

Hi

I've been searching for an answer to this but haven't found one. I'm (currently) using S-Planner as my calendar. There's this thing called "My calendar" which I presume is the local, on phone, calendar. It seems like, when I create a calendar entry, it sets the default as the last calendar I chose so I have that set to my Google calendar which is fine.

The problem is that I've been sent a few .vcs files from my wife's S3 by email. When I open the file in my email app (AquaMail) it opens the calendar's import facility but this always seems to default to "My calendar"; I want it to default to my Google calendar here instead. I can manually choose on that page to select the Google on, but it doesn't 'stick'; every time I try it it reverts to "My calendar".

I tried setting S-Planner up to not display "My calendar" in the hope that it would choose a different calendar as default for importing vcs files but that made no difference.

Does anyone have any ideas?

Thanks
John