You can use an email account different from the email account of the SOMESERVICEUSERNAME to send smartmails. Thus allowing a user friendly sender to be seen as sender on smartmails. To do this, you will need to configure an email account that grants SOMESERVICEUSERNAME the right to send on behalf of the configured mail account.
Microsoft documentation links
To make SOMESERVICEUSERNAME able to send messages on behalf of a MailAgent user, make the configurations described here: http://technet.microsoft.com/en-us/library/aa998291(EXCHG.80).aspx
For more information about setting up Send As permission, see:
Example: A mailbox which allows SOMESERVICEUSERNAME to send on behalf of someone could be MailAgent@lmdom.local
.
See Configure WorkZone Process.