attach a campaign (seminar) to contacts

[jvt]

I've created a campaign, in this case a seminar. For the contacts that
attended, I want to attach the campaign to their history, but "campaign" is
not an option in the "add history item" pulldown list. I know that I can use
"initiated by" to select seminar and then the specific campaign, but this
overwrites the already entered "initiated by" and destroys the CRM principle
of recording customer contacts seeing them evolve in the marketing funnel.
(For example, if somebody responds to a mailing and then attends a seminar,
you want to see both customer contacts and not just the last one).

 

[jvt]

And to add to this: when I initially created the campaign, I couldn't make of
list of contact that were targeted for the seminar (as noted in other posts,
this functionality only is available for email campaigns). Even it this were
possible, it still wouldn't be desired because people that are invited don't
necessarily attend.

So to explicitly pose the question: how do I add a campaign to a contact,
after the fact, or if this is not possible, what is the workaround to create
a record of people attending a seminar, such that I can find them back in the
campaign report for the seminar.