I have just confirmed and will answer the question as to how to transfer the contacts from an iden phone to the 7520 (or probably any BB with compatible SIM).
1) Download
Iden Phonebook Manager (25.3MB) and back up the phonebook from the SIM of the iden phone to your computer.
2) Take the SIM for your Blackberry and put it into the iden phone. Restore the backup to the iden phone (which contains the Blackberry SIM) but be sure not to overwrite the current data (will be an option when restoring).
3) Remove SIM from iden phone and place back in blackberry. Then go to your address book and click the track-wheel. Select SIM Phonebook and the list of entries will be displayed. Click the track-wheel and select Copy All to Phonebook.