You can now choose who your Client Task emails and reminders come from within the Client Task module.
From within the Work's task tab, select the Sent to Client button on the Client Task module.
A model will appear where you can enter who to send the client task to and now who the client task will come from. It can come from the work assignee, client owners, or another colleague. If you would like the email to come from you and you are neither the work assignee or the client owner, select Other Colleague and enter your name.