Windchill mail.from

Hello, We have used Windchill for several years but just for CAD Data Management.  We're now starting to use Promotion and some other functions, resulting in many emails from Windchill.  Email properties are set up as follows:

wt.mail.from=Postmaster@$(wt.rmi.server.hostname)

wt.mail.mailhost=relay.boeing.com

wt.mail.mime.charset=UTF-8

wt.mail.verbose=false

This results in the email from Windchill saying it's from this user:

Postmaster@eng-hbc-wc10.sw.nos.boeing.com

Question: How can we change it so the email is from WindchillSystem@BoeingHTB?

thank you