When I am configuring an action in /admin/settings/actions/configure/

I want to include the user triggering the action as part of the action's email 

message.

How can include the username when creating an action of type

"Send email to all users in a specific role(s)"

I tried '$username', '%username', since they work with "Send an email..."

type action, but it did not work with the "Send email to all user in a specific role(s)" .

Thanks,

Néstor