Installing Ning to Buddy Press

I would like to start importing my members from Ning (using your plugin) but I would like to be able to import the users first and THEN send the e-mail with their new password, as I would like to check if the members were imported correctly. My question is can I start importing and send the e-mail later on or is this an automatic function (means as you import the e-mail is send out at the same time)
Please advise.

Thanks
Flavio