Delete phonebookentry with gnokii

[gnokii]

Hi!

Is it possible to delete a phonebookentry with gnokii?

I can create or change an entry with:
$ gnokii --writephonebook
Test;123;SM;1;5
^D

But can I delete it? (Or how?)
I tried:
$ gnokii --writephonebook
;;SM;1;5
^D
But then I get "Format problem on line 2 [;;SM;1;5]".

I can delete it using xgnokii, so I think it should work with gnokii, 
too.

cu