[O] my capture template generates a literal "%?"

[G]

Hi,

I am using Emacs 24.1 in Win7 (64bit) and Org 7.8.11.
I would like to have a capture template that just puts me at the end of 
my journal in plain text (although date tree) after a custom time stamp 
(e.g. 09:13). I tried the following
    ("p" "Plain Journal" plain (file+datetree 
"C:/Users/Geralb/Documents/privat/org/MyAgenda.org")
         "%<%H:%M>\n\n%?"
     :unnarrowed t :empty-lines 1)

But in this template a literal %? is written and point is thereafter.

I tried another template
    ("e" "Entry Journal" entry (file+datetree 
"C:/Users/Geralb/Documents/privat/org/MyAgenda.org")
         "* Um %U von %a\n\n%?\n"
     :empty-lines 1 :unnarrowed t)

And this seems to work, but it's not what I would like to have.

Did I write the template wrong?

Geralb