get drive letter from drivemapadd?

Hi,

Im using DriveMapAdd to mount a network folder to a letter and heres my command

DriveMapAdd("*:","\\nas\share")

As im using * I dont know what letter will be used until it's mounted, and when my script is finished I want to use DriveMapDel to unmount it automatically but there is nothing in the documentation for the * when using this command, how can I get it to store the correct value in a variable so I can refer to the correct drive letter later?

Thanks