I would put the MSI in it's own folder on the DM ... example c:\msi
Right-Click on All Software or Software Package Library
Select Import > MSI-package
You should get the MSI Package Registration Wizard Window
Select Register MSI package to the Software Library Window Next>
Browse to the MSI file Next>
CD-options ... Do nothing Next>
Customize ... Do nothing Next>
Finish
Then for the Procedures you want to use in the Catalog check off catalog enabled
and then copy the procedure to the Catalog folder.