Creating a notification workflow for cases in Sugar BPM

Good afternoon,

I have a question regarding the creation of Workflows in Sugar BPM (We don't have Sugar Serve). I also asked Sugar Support about this but they redirected me to the Sugar Club as Sugar BPM workflows are out of the scope of their support. 
I think I almost configured the entire workflow. However it is not yet working the way I want it to. I would like to configure a Workflow in which an assigned user gets a notification when an (external) client sends an e-mail as a reply  to a case. 
In Process E-mail template I configured the following:
The target module (I thought) is E-mails as I want the notifications when a client replies, to be sent to the assigned user on a case (see screenshot below):
After that I configured the Process definition in Sugar BPM. For this I did the following:
I chose the e-mail direction to be incoming and to only be applicable to updated records (as I only  want the e-mail to be sent out when a client replies to an e-mail.)

After that I configured the e-mail direction to be an outgoing e-mail (as the Sugar user needs to be notified). And I configured the following:
I chose the e-mail template that I configured in the process e-mail template and I want the e-mail to be sent from the e-mail system. 
In the To: field I applied the following setting: User is assigned to cases related to e-mails. Because I want the e-mail to be sent to the assigned user to a case. 
After the e-mail has been sent out to the assignee, the workflow ends.
I think I almost created the workflow, but it seems that it needs some fine-tuning. 
Thank you very much for your answer!
Best regards,
Maike