The only method that they describe involves exporting your extensions and names from the PBX using ASA, and importing them directly.
The instructions (what little there is of them) is VERY particular about the format of the .csv file you're creating. You'd need to export the information from the PBX, open it in an editor (like an Excel spreadsheet) that can limit the data to the information required, save as a .csv and then import to OSPC. It's a very annoying process.
If you happen to have a network LDAP available, I can help you with connecting OSPC to that. It took me DAYS, but I finally got it working.
Carpe dialem! (Seize the line!)