VB6 (using vbSendmail) to send ICS Invitation to Outlook

[Bobbles]

I have an existing VB6 app, that creates Tasks with Dates and Times.
I currently use vbSendMail for other purposes, but not for Tasks yet.
User has asked that in addition to the internal bookings, that I also send an email to the staff members, so that they can open the email in Outlook, and it automatically realizes that it is a Calendar Invitation, which it can load into the user's Calendar.
I would prefer not to 'automate' Outlook, as this occurs in a complex/busy part of my program.
What i would like to do, is create a text file (.ICS) with the necessary Dates/Times, and use vbSendmail to attach that file and send it to the staff members' Outlook email addresses.

In my attempts to explore the format of the ICS file, I have used my Google Calendar to send an invitation.
The one that it sent to my Outlook email address, did open up properly in Outlook.
I also got Google Calendar to send one to my non Outlook email.
It duly arrived with an ICS attachment.
When I tried attaching that file, and sending it to my Outlook email address, Outlook did not realize that it was an Invitation.

Any help would be greatly appreciated.

PS IS THIS IN THE WRONG FORUM ?
I was not sure whether this should be in the general VB6 Forum.
Please advise if you think I should move it