thanks for the feedback on my issue.
i just ended up programmatically using the Report.Tag property to get my value into the report's xml definition file so that i can display the value.
to clarify the situation, i have a front-end web app that collects report criteria and modifies the C1 report XML file for the correct connection string and I place the criteria into the modified report sql statement dynamically before the report is run and rendered as pdf in a browser window.
on my report layout, i needed to include the name of the person who ran it dynamically from the ASP.Net session, and it seemed that i needed an easy way to put that into my report's XML definition so that i could display it.
what i did was created a report.tag element in the report's xml source and then refered to report.tag to display it.
i don't think i could use a report field as you suggested because i needed to have my custom username added to the report xml definition BEFORE the report ran, or am i missing something in setting up a report field?