Problem with sectioning function for LaTeX export

[Sebastian Hofer <sebhofer@gmail.com>]

Hi all,
I'm trying to write my own sectioning function for latex export of my 
CV. What it does is to read out some property of the given headline and 
pass it to a latex command:

(defun my-org-cv-sectioning (lvl heading)
   (let ((year)
         (formatlist)
         (cleanheading (substring-no-properties heading 1)))
     (with-current-buffer (org-find-base-buffer-visiting "cv.org")
       (let ((headingpoint (find-custom-id cleanheading)))
         (if headingpoint
             (progn
               (goto-char headingpoint)
               (setq year (org-entry-get nil "YEAR"))))))
     (setq formatlist (nth (- 1 lvl) my-org-cv-sectioning-list))
     (list cleanheading
           (format (car formatlist) (if year year "") cleanheading)
           (format (car (cdr formatlist)) (if year year "") cleanheading))))

The function find-custom-id returns the point of the heading, 
my-org-cv-sectioning list contains the customized latex commands. As you 
may see, I'm an elisp newbie, so excuse the coding style, or even 
better, make suggestions for improvements! There might be a much nicer 
way to read out the wanted properties (also cf. point 2 below), so if 
you have any suggestions on that, I would be glad to hear them!

Anyway, there are currently two problems:

- The function reads out the properties correctly, but the export 
command throws an error. So I guess I'm not getting the format of the 
output right, but I can't really make sense of the description in the 
org-export-latex-classes docstring. Currently the function is returning 
something like this: ("Heading" ("\section[year]{Heading}" 
"\section*[year]{Heading}")). Isn't this what it's supposed to look 
like? The error message is the following:

Debugger entered--Lisp error: (wrong-type-argument stringp nil)
   format(nil "Heading" "")
   org-export-latex-subcontent(<snipped>)
   org-export-latex-sub(<snipped>)
   org-export-latex-global(((<snipped>))))
   org-export-as-latex(nil nil nil "*Org LaTeX Export*")
   org-export-as-latex-to-buffer(nil)
   call-interactively(org-export-as-latex-to-buffer)
   org-export(nil)
   call-interactively(org-export nil nil)

- As you can see I am using org-find-base-buffer-visiting find the 
buffer of the org file, but of course its argument can't stay hardcoded 
like this. I could also use the org mapping function, but still I would 
need filename. Can someone give me a hint how to solve this in a nice way?

Thanks for any help and thanks to Carsten for his incredible work! I 
keep getting surprised be the capabilities of org-mode almost every day.
Cheers, Sebastian