[TYPO3-seminars] column cnum of table fe_users in emailnotification for organizers

[Christian Spiegel]

Hallo,

how can i get the client number - column cnum in the table fe_users  - 
in the notificationmail for origanizer.

I tried:

plugin.tx_seminars {
   showFeUserFieldsInNotificationMail = cnum, ...
}

but it doesn't work, it only renders an empty

Cnum:

in the mail to the organizer.
In the documentation is writen "...allowed values are all column names 
from fe_users."

Any idea?

Thanks
Christian