if you have an existing post that you want to show in a different channel, you can edit the message and cross-post. This will add the top-level post to the different channel, but will not include the full set of replies. We will keep this request in mind as we evolve the cross-posting feature in the future and update if the status changes.
Details on cross posting can be found here: https://support.office.com/article/cross-post-a-channel-conversation-in-teams-9c1252a3-67ef-498e-a7c1-dd7147b3d295.
This feature is on the backlog. I will update you when we have more details to share.
It looks like some people in the thread below have figured it out — we actually have this. You can start a chat both ways; the system will automatically recognize if this person is on Skype for Business or on Teams.
Thanks and let me know if you have any questions.
An error occurred while saving the commentSara H commented
Mine is not working as you say it should. When I write a message to someone who doesn't have Teams, but has S4B, they don't get a message, but instead get an email later in the day saying they missed a conversation from me. And since I also have S4B installed, messages not initiated in Teams for me only show up in S4B. It'd be nice if I could set my default to Teams so that messages show up there and only there.