How to print User Code on Crystal Report Forms?

Has anyone figured out how to get the 3-digit user code to print out on Crystal Report forms?  I know there is an option you can check in Company Maintenance, Preferences tab, for "Print user logon on Reports," which only prints the user code on reports. I want to include a user code on an invoice form and other forms. I received one suggestion, to include the user code as a sub-report, but that may slow down the processing of printing the forms. I found the user code field in the SY_User table, but can't figure out how to link it to the SO_InvoiceWrk table, or how to otherwise get it to display on the form.  Thank you.

(Sage 100 ERP v.4.5 & Crystal v.11.5.)

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