SeeYou Mobile registration key has three important fields - serial number, name of the customer and the key. Here is a typical example:

Serial number: 12345, Registered to: Your Name, Registration key: 5SKKQ-S3A-TSDW, for SeeYou Mobile

In order to register SeeYou Mobile on your PDA or PNA device you need to enter your name in the field "Registered to" exactly the same as it is written in the key (big or small letters are not important) then enter the key in the field "Registration key"