[BlueOnyx:11162] DNS txt record setup

[Wisja.net]

Hi List,

One of my users has an Office365 account and wants to add his domain to it for email.
So he send me a short description from Microsoft for the creation of a TXT record.
When trying to do this with the GUI, it tells me that the @ is not a valid character.

So I suppose I have to put it in the .include file of the domain.

Alias or hostnaam: @
TXT record: MS=ms123456789 (this number is different for real)
TTL: 1 hour

Could someone point me in the right direction on how my include file should look like?
Or does anyone have other options for Office365?

With kind regards,

Wisja