How do I upload attachments through the Jira import wizard

[Denning Coates]

I am doing a bulk export of tickets from an external system (TFS) and several hundred of these tickets have attachments that need to come over.  We viewed the TFS4JIRA add on and decided to not use it for multiple reasons.  We'd rather do an export and import of the tickets, but what is the best approach to take for ensuring attachments are part of the Jira import process?