cannot manually select Automator workflows in iCal

I know That the Way, Apple intends that we create an Automator workflow as an iCal alarm is to create a new iCal alarm in Automator, and once you save it it automatically creates a new event in iCal. Unfortunately, that's not the way I want to work… I already have dozens of iCal alarms configured, and I'm trying to prep them for Mountain Lion: the currently open AppleScript's but all of my Apple scripts need to be converted to Automator workflows for Mountain Lion. So I was hoping to quickly duplicate previous iCal workflows, then reselect them from within existing events in iCal. Sadly, all of my iCal Automator workflows appear as greyed out in my File Open dialog when attempting to select a new file to run within my iCal alert.

I don't want to have to delete all of my iCal alarms and start over creating them anew. Perhaps I am missing something simple?