Send with digital signature by default

Hello,
is it possible to set up K-9 to send my digital signature by default?
If K-9 would also send my public key, that would be great.

At the moment I have to activate the digital signature for every email, which I keep forgetting.

I would be very happy if you had a solution.

I want/need this too please!

If this feature is imperative to you, you may want to consider R2Mail2 or Nine.