How to change work item "Created By"?

We have some work items which were created manually (rather than using
the Bugzilla importer), and the data came from another RTC project. The
Created By field is now set to the person doing the data creation,
instead of the person who originally opened the work items in the old
project.

Is there any way to change the Created By field values so they're correct?

I know the 2.0 csv importer will let me set this field upon import, but
that doesn't help me with today's 1.x project.

Thanks!