How to automatically add a line item to an order?

Does anyone have any suggestions for how to add an item to an order automatically, based on properties of the order?  We'd like to add an item at order Submission if two flag fields on the order are set.  The item's just serving as a "flag" for a downstream system and won't have any prices, eligibility, compatibility, etc. restrictions and won't remain on the account as an asset.

I haven't had much luck finding anything online or in the Siebel documentation that addresses this situation.  So far, I've tried using a workflow that calls a Siebel Operation step to insert a record into the Order Entry - Line Items (Simple) BC, and a different workflow that called the AddItem method of the eConfigurator BS; neither was successful.