(interactive "rP") valid?

[Thorsten Jolitz]

Hi List, 

function 'org-table-convert-region' uses (interactive "rP") and has the
following signature:

,---------------------------------------------------------
| (org-table-convert-region BEG0 END0 &optional SEPARATOR)
`---------------------------------------------------------

Non-interactively, the function works as expected:
different behaviour conditional on SEPARATOR being nil, an integer, '(4)
or '(16).

However, used interactively, SEPARATOR is always nil when 'C-u <digit>
M-x' is used.

Is (interactive "rP") not a valid combination?
Or is this a bug in Emacs?

-- 
cheers,
Thorsten