A billing can also be adding during the Send and Sync Process.
Open Outlook

Choose to create a New Email
Create a New Email

After adding the information as needed in the email.
Click the Send and Sync - AdvologixPM button
Contact/Matter Selection & Billing Pop-up.

Choose the Sync details and add the billing
Fill in the appropriate information
Rate Amount will change to the Default rate - from the associated matter record chosen (as set in Advologix)
Click SYNC
Clicking 'Add Billing' Brings up the Billing Pop-up

Fill in the appropriate information
Rate Amount will change to the Default rate - from the associated matter record chosen (as set in Advologix)
Click Add Bill