On outlook.com you can now change the default From address to your alias. That way, any mail you sent from your outlook account will be sent from the alias; even on your devices.I have a default @live.com account and an @outlook.com alias. Currently, the only way (with outlook.com and WP, at least) to send email from that alias is via the web interface.
Nah, that's not what we want.
I want the reply to an email, to come from the alias address it was sent to.
Or.. pick the alias I want to send from when I create the email.
You can do all of this in the web interface.