We recently purchased a hosted solution for Mantis Bug Tracker via a2 Hosting. We have the website set up and we have some basic configuration done through the Mantis user interface. We are trying to import issues in bulk either with an Excel, CSV, or XML file or command. Going through the manage and configuration options I did install the "Import/Export issues 1.0" plugin like such:

But we have no idea on how to actually take a file with multiple records and upload it to a project or otherwise to Mantis Bug Tracker "Issues".
Please note that with the hosted solution we do not have access to any of the source code. We're stuck with using the Mantis user interface. If it is possible to bulk import please advise.
Thank You,
Alexander Daniel Campos