Customize Zoho CRM Portal Invite

Customize Zoho CRM Portal Invite

Hi! Our Company just started using the Client Portal Function in Zoho CRM. I am currently looking for a way to customize the email our clients will get, when we invite them via the CRM. 

I could not find a way to change this message and currently it does not look very inviting (and is signed only by "administrator", which doesn't help) Is there any way to customize the invite email?