E_mails composed from within CRM, CONTACTS tab, use ZOHO.com account as default - Need to change it

E_mails composed from within CRM, CONTACTS tab, use ZOHO.com account as default - Need to change it

Our firm just purchased ZOHO Mail, as an add-on to our  CRM Professional.
We use various e-mail accounts -all gmail.
We want  to write to our customers using one of our gmail accounts - not the ZOHO.com account.

How do I define one of our gmail accounts as the default account when using:
 CONTACTS » EMAILS » SEND MAIL ??

Note - If I compose an e-mail via the EMAIL tab,then compose, the e-mail account in the compose editor will be the one I define at the left side of the screen - gmail, or  zoho. 

This is not a solution because those emails will not be registered (attached) to the email field inside CONTACTS. 


Please help.
Thanks