If you use the Teamgate functionality to attach emails to your Leads, Companies, People, and Deals cards, then you're aware that emails are attaching only from the email address you use to login to Teamgate. If you are using several email addresses- add them to your user profile. Then, when you send your email to a customer and add our server email address in the CC or BCC line, it will be attached to your customer's CRM card.
You will find the option to add new email addresses in the "My Profile" section. Enter email address and click "Save".
Here's the additional information about "How to attach an email copy to the company or contact card".